Hi all, when I update IIS, I get the following error on each page with Telerik. When I click F5 (refresh), the page loads well and dont appear anymore. I'm using Win 2003 and Win 2008 with IIS. System.OverflowException: Arithmetic, casting or conversion operation overflowed or underflowed. (Exception from HRESULT: 0x80131516) at System.Reflection.PseudoCustomAttribute._GetSecurityAttributes(RuntimeModule module, Int32 token, Boolean assembly, Object[]& securityAttributes) at System.Reflection.PseudoCustomAttribute.GetCustomAttributes(RuntimeAssembly assembly, RuntimeType caType, Boolean includeSecCa, Int32& count) at System.Reflection.CustomAttribute.GetCustomAttributes(RuntimeAssembly assembly, RuntimeType caType) at System.Reflection.RuntimeAssembly.GetCustomAttributes(Boolean inherit) at System.Web.UI.AssemblyCache.GetAjaxFrameworkAssemblyAttribute(Assembly assembly) at System.Web.UI.ScriptManager.get_DefaultAjaxFrameworkAssembly() at System.Web.UI.ScriptManager..ctor() at Telerik.Web.UI.RadScriptManager..ctor() Regards, Rastislav