>I got this error as a result of a syntax error passing parameters to a method from within another method in the object. My conclusion from that is that your problem could be just about anything. Good luck.

Thanks for the luck. I found it.
I tried to release a classlib when the dll get destroyed.
Sometimes it goes well, sometimes it hangs the dll without generating an error.
The directory, where the ASP resides wich creates and loads the dll, is an Virtual Application in IIS. The dll is pooled and actualy not destroyed(if so it seems to be). Windows tries to call that pooled dll instead of loading a new one. Because the dll hangs all the calls will fail.