How to fix a security warning on a web form?

Question

hi, I have added a new form which I have modified, and it is coming up with a security warning (see attached screenshot)
Is there any reason why this is happening and is there anything I can do to make it secure?
Form is here:
(www.eastsidestudios.com.au > book now > view cart > checkout)
The checkout form is the one that has the security warning.
This is the code on the form:
<div class="checkOut">
<h3>CHECKOUT</h3>
<h5>* These fields are required</h5>
<form action="http://www.eastsidestudios.com.au/FormProcessv2.aspx?WebFormID=42582&OID={module_oid}&amp;OTYPE={module_otype}&amp;EID={module_eid}&amp;CID={module_cid}" enctype="multipart/form-data" onsubmit="return checkWholeForm73108(this)" method="post" name="catwebformform73108">
    <table width="600" cellspacing="0" cellpadding="2" border="0" class="webform">
        <tbody>
            <tr>
                <td colspan="3">
                <table width="600" cellspacing="0" cellpadding="2" border="0" class="webform">
                    <tbody>
                        <tr>
                            <td colspan="3"><label for="Title">Title</label>
                            <br />
                            <select class="cat_dropdown_smaller" id="Title" name="Title">
                            <option value="436503">MISS</option>
                            <option selected="selected" value="436500">MR</option>
                            <option value="436501">MRS</option>
                            <option value="436502">MS</option>
                            </select></td>
                        </tr>
                        <tr>
                            <td colspan="2"><label for="FirstName">Parent First Name <span class="req">*</span></label>
                            <br />
                            <input type="text" maxlength="255" class="cat_textbox" id="FirstName" name="FirstName" /></td>
                            <td colspan="2"><label for="LastName">Parent Last Name <span class="req">*</span></label>
                            <br />
                            <input type="text" maxlength="255" class="cat_textbox" id="LastName" name="LastName" /></td>
                        </tr>
                        <tr>
                        </tr>
                        <tr>
                            <td colspan="3"><label for="EmailAddress">Email Address <span class="req">*</span></label>
                            <br />
                            <input type="text" maxlength="255" class="cat_textbox" id="EmailAddress" name="EmailAddress" /></td>
                        </tr>
                        <tr>
                            <td style="width: 188px;"><label for="HomeAddress">Home Address <span class="req">*</span></label>
                            <br />
                            <input type="text" maxlength="500" class="cat_textbox" id="HomeAddress" name="HomeAddress" /></td>
                            <td colspan="3"><label for="HomeCity">Suburb <span class="req">*</span></label>
                            <br />
                            <input type="text" maxlength="255" class="cat_textbox" id="HomeCity" name="HomeCity" /></td>
                            <td colspan="3" style="width: 172px;"><label for="HomeZip">Zipcode/Postcode <span class="req">*</span></label>
                            <br />
                            <input type="text" maxlength="255" class="cat_textbox" id="HomeZip" name="HomeZip" /></td>
                        </tr>
                        <tr>
                        </tr>
                        <tr>
                        </tr>
                        <tr>
                            <td colspan="3"><label for="HomePhone">Home Phone Number <span class="req">*</span></label>
                            <br />
                            <input type="text" maxlength="255" class="cat_textbox" id="HomePhone" name="HomePhone" /></td>
                        </tr>
                        <tr>
                            <td colspan="3"><label for="CellPhone">Cell Phone Number <span class="req">*</span></label>
                            <br />
                            <input type="text" maxlength="255" class="cat_textbox" id="CellPhone" name="CellPhone" /></td>
                        </tr>
                        <tr>
                            <td colspan="3"><label>Payment Method <span class="req">*</span></label>
                            <br />
                            <input type="radio" value="5" id="PaymentMethodType_5" name="PaymentMethodType" />
                            PayPal<br />
                            </td>
                        </tr>
                        <tr>
                            <td><label for="CAT_Custom_259470">Child 1 Name <span class="req">*</span></label>
                            <br />
                            <input type="text" class="cat_textbox" id="CAT_Custom_259470" name="CAT_Custom_259470" maxlength="1024" /></td>
                            <td colspan="3"><label for="CAT_Custom_259481">Date of Birth Child 1 <span class="req">*</span></label>
                            <br />
                            <input type="text" class="cat_textbox" id="CAT_Custom_259481" name="CAT_Custom_259481" maxlength="1024" /></td>
                            <td colspan="3"><label for="CAT_Custom_259484">T-Shirt Size - Child 1 (holiday camp only)</label>
                            <br />
                            <select class="cat_dropdown" id="CAT_Custom_259484" name="CAT_Custom_259484">
                            <option value=" ">-- Please select --</option>
                            <option value="XS">XS</option>
                            <option value="S">S</option>
                            <option value="M">M</option>
                            <option value="L">L</option>
                            </select></td>
                        </tr>
                        <tr>
                        </tr>
                        <tr>
                        </tr>
                        <tr>
                            <td><label for="CAT_Custom_259475">Child 2 Name</label>
                            <br />
                            <input type="text" class="cat_textbox" id="CAT_Custom_259475" name="CAT_Custom_259475" maxlength="1024" /></td>
                            <td colspan="3"><label for="CAT_Custom_259482">Date of Birth Child 2</label>
                            <br />
                            <input type="text" class="cat_textbox" id="CAT_Custom_259482" name="CAT_Custom_259482" maxlength="1024" /></td>
                            <td colspan="3"><label for="CAT_Custom_259485">T-Shirt Size - Child 2 (holiday camp only)</label>
                            <br />
                            <select class="cat_dropdown" id="CAT_Custom_259485" name="CAT_Custom_259485">
                            <option value=" ">-- Please select --</option>
                            <option value="XS">XS</option>
                            <option value="S">S</option>
                            <option value="M">M</option>
                            <option value="L">L</option>
                            <option value="XL">XL</option>
                            </select></td>
                        </tr>
                        <tr>
                        </tr>
                        <tr>
                        </tr>
                        <tr>
                            <td colspan="3"><label for="CAT_Custom_259472">School</label>
                            <br />
                            <input type="text" class="cat_textbox" id="CAT_Custom_259472" name="CAT_Custom_259472" maxlength="1024" /></td>
                        </tr>
                        <tr>
                            <td colspan="3"><label>I hereby give permission for my child to attend Eastside Studios and I understand that my child will be supervised for the duration of the class camp and/or aftercare hours only. (Aftercare hours only available during holiday camps) <span class="req">*</span></label>
                            <br />
                            <input type="radio" value="Yes" id="CAT_Custom_259476_0" name="CAT_Custom_259476" checked="checked" />
                            Yes</td>
                        </tr>
                        <tr>
                            <td colspan="3"><label for="CAT_Custom_259473">Does your child have any condition/illnesses/allergies that we need to be aware of?</label>
                            <br />
                            <textarea onkeydown="if(this.value.length&gt;=1024)this.value=this.value.substring(0,1023);" class="cat_listbox" rows="4" cols="10" id="CAT_Custom_259473" name="CAT_Custom_259473"></textarea></td>
                        </tr>
                        <tr>
                            <td colspan="3"><label>I give permission for my child to be photographed during the class and understand these photos may be used exclusively for Eastside Studios advertising material. <span class="req">*</span></label>
                            <br />
                            <input type="checkbox" value="Yes" id="CAT_Custom_259474_0" name="CAT_Custom_259474" />
                            Yes<br />
                            <input type="checkbox" value="No" id="CAT_Custom_259474_1" name="CAT_Custom_259474" />
                            No</td>
                        </tr>
                        <tr>
                            <td colspan="3"><input type="checkbox" name="CampaignList_29296" />
                            Subscribe to: Eastside Studios Database</td>
                        </tr>
                        <tr>
                            <td colspan="3"><input type="submit" id="catwebformbutton" value="Submit" class="cat_button" /></td>
                        </tr>
                    </tbody>
                </table>
                </td>
            </tr>
        </tbody>
    </table>
    <script type="text/javascript" src="http://www.eastsidestudios.com.au/CatalystScripts/ValidationFunctions.js"></script>
    <script type="text/javascript">
//<![CDATA[
var submitcount73108 = 0;function checkWholeForm73108(theForm){var why = "";if (theForm.FirstName) why += isEmpty(theForm.FirstName.value, "First Name");if (theForm.LastName) why += isEmpty(theForm.LastName.value, "Last Name"); if (theForm.EmailAddress) why += checkEmail(theForm.EmailAddress.value); if (theForm.HomeAddress) why += isEmpty(theForm.HomeAddress.value, "Home Address"); if (theForm.HomeCity) why += isEmpty(theForm.HomeCity.value, "Home City"); if (theForm.HomeState) why += isEmpty(theForm.HomeState.value, "Home State"); if (theForm.HomeZip) why += isEmpty(theForm.HomeZip.value, "Home Zipcode"); if (theForm.HomeCountry) why += checkDropdown(theForm.HomeCountry.value, "Home Country"); if (theForm.HomePhone) why += isEmpty(theForm.HomePhone.value, "Home Phone Number"); if (theForm.CellPhone) why += isEmpty(theForm.CellPhone.value, "Cell Phone Number"); if (theForm.PaymentMethodType) why += checkSelected(theForm.PaymentMethodType, "Payment Method");if (theForm.CAT_Custom_259470) why += isEmpty(theForm.CAT_Custom_259470.value, "Child 1 Name");if (theForm.CAT_Custom_259481) why += isEmpty(theForm.CAT_Custom_259481.value, "Date of Birth Child 1");if (theForm.CAT_Custom_259476) why += checkSelected(theForm.CAT_Custom_259476, "I hereby give permission for my child to attend Eastside Studios and I understand that my child will be supervised for the duration of the class camp and/or aftercare hours only. (Aftercare hours only available during holiday camps)");if (theForm.CAT_Custom_259474) why += checkSelected(theForm.CAT_Custom_259474, "I give permission for my child to be photographed during the class and understand these photos may be used exclusively for Eastside Studios advertising material.");if(why != ""){alert(why);return false;}if(submitcount73108 == 0){submitcount73108++;theForm.submit();return false;}else{alert("Form submission is in progress.");return false;}}
//]]>
</script>
</form>
</div>

Answer 1

The problem is in <form action="http://www.eastsidestudios.com.au/FormProcessv2.aspx?WebFormID=42582&O ID={module_oid}&amp;OTYPE={module_otype}&amp;EID={module_eid}&amp;CID={mo dule_cid}"
You have to remove http://www.eastsidestudios.com.au from the action URL and make it relative:
<form action="/FormProcessv2.aspx?WebFormID=42582&O ID={module_oid}&amp;OTYPE={module_otype}&amp;EID={module_eid}&amp;CID={mo dule_cid}"
Cheers,
-mario