Hello lcarneiro,

Thank you for posting on Infragistics forum.

One possible reason for this exception is unregistered/missing ASP.NET AJAX 1.0 extensions. If you did not installed this extensions see how you can do this in the following article - http://blogs.msdn.com/b/webdevtools/archive/2007/07/30/using-vs-2008-to-target-asp-net-ajax-1-0.aspx

Other possible reason is missing or with other version “<httpHandlers>” section in the project “web.config” file. How you can correct this you can see in the following forum thread - http://forums.asp.net/t/1207960.aspx/1/10

Follow these articles to modify your application and let me know if the exception is still present.

 I saw this post on http://encosia.com/asmx-scriptservice-mistakes-installation-and-configuration

“Thankfully, ASP.NET 4 has taken steps to reverse the trend of ever-enlarging baseline web.config files. By moving common configuration items such as the ScriptService’s HttpHandler to the default machine.config, each individual site need not include those configuration elements in their specific web.config files.

Unless you go out of your way to manually remove their HttpHandler, ASMX ScriptServices will work automatically in any ASP.NET 4 site.”

I checked the References and System.Web.Extensions appointing  to C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.0\System.Web.Extensions.dll

I don´t understand why can I drilldown one time (believe AJAX is working) and cannot drilldown another record.

I appreciate any suggestion