[Lynne]

Download your style (Styles & Templates > Download/Upload Styles) and then Upload the style but click the Create New Style one and give it a new name and No Parent. Now you can go and Revert templates in that style to figure out which one is causing the problem. Basically, send yourself a PM, revert a template, click on your site (remember to do this which using this new style) and see if the pop-up comes. If not, send another PM, revert another template, click on another link on your site and see if the pop-up comes. Keep doing that until eventually reverting one of the templates will fix it and you'll know it's that template.