I have downloaded the CTP today, followed the video at
http://forums.infragistics.com/aspnet/media/p/79416.aspx, but am having the error
The type 'Infragistics.Web.UI.DataSourceControls.WebHierarchicalDataSource' exists in both 'c:\WINDOWS\assembly\GAC_MSIL\Infragistics35.Web.v9.1\9.1.20091.1015__7dd5c3163f2cd0cb\Infragistics35.Web.v9.1.dll' and 'c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\website1\bbf23140\6a951561\assembly\dl3\d97fbe34\00fd4926_0512ca01\Infragistics35.Web.v9.2.DLL'
Has anyone managed to use this control successfully?
It sounds like you have two versions of the WebHierarchicalDataSource controls installed (9.1 in the GAC and 9.2 in the shadow bin folder for this Web app). Make sure all <%Register ... directives at the top(s) of your Web pages (with the ig TagPrefix I believe) is referring to the 9.2 version specifically and that you do not have some references to 9.1 assemblies and other references to 9.2 assemblies in the same Web project.
The good news is that the NetAdvantage ASP.NET 2009 Vol. 2 controls have now been released, so you can install it instead of the August CTP controls.