>I can't seem to get COMRETURNERROR to work.

I don't think you need to encapsulate a classes error method (with this - endwith) since it is already inside the class. COMRETURNERROR reports back to the ON ERROR trap in your client and should be reported from that method. Otherwise it looks okay.

Here is a little project that uses COMRETURNERROR inside a custome class compiled to a DLL: download #9840