ScriptResource not loading

Question

This is an interesting problem...

I've got an ASP.NET 3.5 web application. It's relatively simple - a content page based on a master page, with a couple of usercontrols on the page.

There are a total of four controls on the page; two are custom controls and two are Ektron CMS controls.

For some reason, I've been getting 'Sys is undefined' Javascript errors. The Firebug error console also throws an "ASP.NET client framework failed to load" error. I can't figure out why this is happening.

The kicker - if I take the controls that don't work completely out of the content page, they work just fine. It's obviously something in the content page trashing the framework, but I haven't been able to figure this one out.

I've looked through several dozen articles before posting, including suggestions like:

• Repairing the .NET framework (didn't work)
• Various web.config tweaks (either already there or didn't work)
• regiis -i command (I don't think this will help, since the controls do work when I'm not using the content page)
• Commenting out custom scripts on the user controls (didn't work)
• Commenting out the other user controls on the page (didn't work)
• Create a blank page and drop only the control I'm interested in on the page (this actually works)

Has anyone seen something like this before? It's got to be something in that content page, but I'm struggling with what.

EDIT

I noticed while stepping through the code the UserControl's PAGE_LOAD event fires three times; on the third time the code throws an error. (I'm still trying to get my head around the error that's being thrown)

EDIT

I wanted to add this in case someone else sees this error. It turns out the problem was being caused by a Scriptmanager on the page template that wasn't needed.

When I took the Scriptmanager off the page, everything worked fine and the framework load error went away. I figure this problem must have broken other scripts and prevented them from running later on down the page.