ADO.NET Dataservices: Fancy Error Part II

Today my first Silverlight 2 application goes live. It is a customer feedback app for the ADC 08 conference. After successfully installed and tested a few hours everything went well. But then data was not show. on direct call of ado.net dataservice vcs in browser following error comes up

Die Datei oder Assembly App_Web_znszzsfo, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null oder eine Abhängigkeit davon wurde nicht gefunden. Das System kann die angegebene Datei nicht finden

The rest of the asp.net site works well.

As I was used to from earlier experience   with ADO.NET dataservices on IIS 6 the error message is not what it seams. I tryed restart of IIS, delete temp ASP.NET compiled files of website. Nothing helped.

The original reason was a change of the server ip address by admin. Workaround was to delete temp files from root folder.