That's a strange problem indeed. If you cannot replicate it locally, then it is possible that the issue is related to web resources, so please review the help topic on Web Resources Troubleshooting
. I hope this helps.
the Telerik team
If you want to get updates on new releases, tips and tricks and sneak peeks at our product labs directly from the developers working on the RadControls for ASP.NET AJAX, subscribe to their blog feed