Skillbuilders modal popup v2. - popup does not open, can't figure out why..

Question

Hi, I am using APEX v4.1 and have used skillbuilders modal popup v2 successfully in the past. For some reason, it is working on one page (calling page 700 to pull up popup page 360) but not working on another page (calling page 900 to pull up popup page 920).
Both modal popup pages are called from HTML buttons using dynamic actions.
Does anyone have ideas for debugging.
thanks, Karen
ps. when I run the console debug, I receive the following on loading the page. I am completely new to javascript and have no idea what this means....it does not happen on p700, only on page 900
SCRIPT5007: Unable to get value of the property 'length': object is null or undefined
apex_4_1.min.js, line 18 character 88940
function initTabForm(a,b,d,h,g){
var f="#init_row_"+a;
gErrItems=g;
gChangedItems=new Array();
gNumRows=h;
gNewRows=0;
gTabFormRegionID=a;
gTabFormReportID="report_"+a;
gTabForm=apex.jQuery(f).parent();
gTabFormDefaultBG=apex.jQuery(f).children("td").css("background-color");
gTabFormInitRow=b+apex.jQuery(f).html()+d;
apex.jQuery(f).remove();
var c=$x_FormItems($x(gTabFormReportID));
for(var e=0;
e<c.length;
e++){
apex.jQuery(c[e]).attr("autocomplete","off");
if(c[e].name!="X01"){
gTabFormData[e]=c[e].value
else{
gTabFormData[e]="0"
apex.jQuery(".row-selector").click(function(){
highlightRow(gTabFormRegionID,this,apex.jQuery(".row-selector").index(this))
apex.jQuery(document).bind("apexbeforepagesubmit",function(){
apex.jQuery("input[name$=NOSUBMIT]",apex.jQuery("#"+a)[0]).each(function(){
$x_disableItem(this,true)
apex.jQuery(f).remove()
Edited by: KarenH on Sep 28, 2012 10:39 AM

Answer 1

Thanks Pete.
This is a large application, and I have had difficulty posting to apex in the past because the schema is too large and cannot be exported...but at least it gives you an idea.
I am trying to rewrite p900 as it is much too complicated, and thought the modal popup would help in terms of adding new rows and validating, rather than using collections. This code was inherited, so I am a bit confused myself...but hoping to make progress.
The button in question is called TRIPHEADER (add/edit trip header).
https://apex.oracle.com/pls/apex/f?p=4550:1:33303433963:::::
workspace: KEH813
user: guest
pwd: fish
if you have trouble with that, access my development site:
http://warsaw-grouper.accsp.org:7777/pls/safisd_11/f?p=4550:1:0:::::
workspace: SAFIS
user: guest
pwd: fish
you will need to run application 200 and logon as MDFISHER/SHARKBAIT
go to FAVORITES (p900) and press ADD/EDIT TRIP HEADER....nothing happens.
if you go to menu-->FISHER INFO and press ADD/EDIT EMAIL, you will see the modal successfully appear.
thanks again. Karen