Error on IE - 'Syntax Error' if CustomErrors are On while loading pages having telerik grid

[Sonia]

We are facing an issue on those pages containing telerik grid. When the page loads, there is an error in IE which says - 'Syntax Error' Line 3 Char 1. We get this error only if CustomError is set to On in the web.config file.

<customErrors mode="On" defaultRedirect="General/Error.aspx">

    <error statusCode="403" redirect="General/Error.aspx"/>

    <error statusCode="404" redirect="General/Error.aspx"/>

</customErrors>

 

 

It works fine on pages where telerik grid is not present. We are using the version 2010.1.519.35 of Telerik.Web.UI.dll and Telerik.Web.Design.dll.

When we tried to debug the error, we got the message - 'Sys is undefined' and debugging took us to the file WebResource_2.axd. Seeing the previous threads on this error, we tried to modify the web.config with changes suggested in http://www.asp.net/ajax/documentation/live/ConfiguringASPNETAJAX.aspx and also added

<location path="Telerik.Web.UI.WebResource.axd">

<system.web>

<authorization>

<allow users="*"/>

</authorization>

</system.web>

</location>

but both the things did not work.

Please have a look and let us know if you need any other details.

Attached the global.asax code for application_error event and the file we get when we debug the IE js error.