Help: SOAP Response Fault when big string is returned

Question

Hello all, I'm quite newbie on Flex and SOAP, so sorry if I'm making an obvious question
I  have an application in Flex that consumes a webservice, and everything  runs smoothly until I try to return a big string, which I find to be  odd. In my tests, when the string is over 490 characters, I get the  following message:
SOAP Response cannot be decoded. Raw response: faultCode="DecodingError" faultDetail="null"
I  made a PHP client, just for testing, to consume the same webservice,  that calls the same operation. But in this other client, I get no errors  and the string is returned complete, with no problems.
Sorry for my english, and any help will be very appreciated! Thanks!
Here is my script:
<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
               xmlns:s="library://ns.adobe.com/flex/spark"
               xmlns:mx="library://ns.adobe.com/flex/mx" minWidth="955" minHeight="600">
    <fx:Script>
        <![CDATA[
            import mx.collections.ArrayCollection;
            import mx.rpc.events.ResultEvent;           
            [Bindable]private var testValue:String;
            protected function floappService_variableTestResultHandler(event:ResultEvent):void
                this.testValue = event.result as String;
        ]]>
    </fx:Script>
    <fx:Declarations>
        <s:WebService id="ws"
                      wsdl="mywebservice?wsdl"
            <s:operation name="variableTest"
                         result="floappService_variableTestResultHandler(event)"
                         fault="mx.controls.Alert.show(event.fault.faultString)"/>
        </s:WebService>
    </fx:Declarations>
    <mx:VBox width="100%" height="100%">
        <mx:Form width="100%" height="100%">
            <mx:FormItem>
                <mx:HBox>
                    <s:Button label="Variable Test" click="ws.variableTest()"/>
                    <mx:Text text="{testValue}"/>
                </mx:HBox>
            </mx:FormItem>
        </mx:Form>
    </mx:VBox>
</s:Application>

Answer 1

Here is the raw response in the case that I get no faults (string with 490 'A's)
HTTP/1.1 200 OK
Date: Tue, 21 Sep 2010 17:36:46 GMT
Server: Apache/2.2.14 (Ubuntu)
X-Powered-By: PHP/5.3.2-1ubuntu4.2
X-SOAP-Server: NuSOAP/0.7.3 (1.114)
Content-Length: 1027
Vary: Accept-Encoding
Connection: close
Content-Type: text/xml; charset=ISO-8859-1
<?xml version="1.0" encoding="ISO-8859-1"?>
<SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/" xmlns:tns="http://fusionforge.inteligis.paqtc.org.br">
<SOAP-ENV:Body>
<ns1:variableTestResponse xmlns:ns1="http://fusionforge.inteligis.paqtc.org.br">
<myReturn xsi:type="xsd:string">AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA</myReturn>
</ns1:variableTestResponse>
</SOAP-ENV:Body>
</SOAP-ENV:Envelope>
And here is the case when I get the fault (string with 491 - or more - 'A's):
HTTP/1.1 200 OK
Date: Tue, 21 Sep 2010 17:40:40 GMT
Server: Apache/2.2.14 (Ubuntu)
X-Powered-By: PHP/5.3.2-1ubuntu4.2
X-SOAP-Server: NuSOAP/0.7.3 (1.114)
Content-Length: 1028
Vary: Accept-Encoding
Connection: close
Content-Type: text/xml; charset=ISO-8859-1
<?xml version="1.0" encoding="ISO-8859-1"?>
<SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/" xmlns:tns="http://fusionforge.inteligis.paqtc.org.br">
<SOAP-ENV:Body>
<ns1:variableTestResponse xmlns:ns1="http://fusionforge.inteligis.paqtc.org.br">
<myReturn xsi:type="xsd:string">AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA</myReturn>
</ns1:variableTestResponse>
</SOAP-ENV:Body>
</SOAP-ENV:Envelope>
I checked both XMLs "well-formedness" on W3 XML Validator (
http://www.w3schools.com/XML/xml_validator.asp), and got no errors.
The  only difference between both responses is the Content-Length, so I'm  guessing that it has something to do with it (don't have any idea of  what/why)