Sorry to see you're having trouble. Your code snippet looks correct. You can obviously remove the unused "Assembly" and "Name" properties from your ScriptReference, but otherwise things look okay.
Have you tried debugging this problem yet? If not, I'd suggest trying a couple of things:
- Try using a "regular" ScriptManager to see if that solves the problem. If it does, then...
- Try re-adding the Telerik ScriptManager. If that re-breaks the page, then...
- Try re-adding the older version of the Telerik ScriptManager. If that works then we've found a problem with the version you're using.
Give those things a try and let me know what you find.