ASP.NET Ajax framework failed to load client side framework

 I face below errors at a same time.

ASP.Net Ajax framework failed to load client side framework
Microsoft JScript runtime error: 'Sys' is undefined
and Telerik is undefined.
 
If somebody else also got this error, below is what i did to resolve this error.
I had below in my web.config 
 
<add name="Telerik_Web_UI_WebResource_axd" path="Telerik.Web.UI.WebResource.axd"
                 type="Telerik.Web.UI.WebResource" verb="*"
                 preCondition="integratedMode,runtimeVersionv2.0"/>  
 
 
I removed runtimeversion2.0 and it worked well.
 
Just to update you that it was working well in IIS6.0 but error occured when i deploy it on IIS7.0
 
So the above entry was in <system.webServer> tag, which is basically for iis7 specific.
 
It took my lot of time to resolve this issue.