Setting up a catch-all email in Exchange 2007 can be a little bit tricky. The problem is that the server accepts the message, and then sends a NDR. PopGrabber has no way to know at the point of the delivery that the message was rejected.
You can install a Catch-All Agent for Exchange 2007 (download at
http://www.codeplex.com/catchallagent/). You need to configure the default address in an XML file and manually install the agent.
Let us know if this helps.
Regards,
Eclarsys Support