Hi,
The error is due to the default ASP.NET security limitation of 4MB for file uploads. My recommendation is to decrease the size of your archives to less than megabytes.
Kind regards,
Rumen
the Telerik team
Consider using RadControls for ASP.NET AJAX (built on top of the ASP.NET AJAX framework) as a replacement for the Telerik ASP.NET Classic controls, See the product support lifecycle here.