Type mismatch when passing connection object

A couple of days ago we started getting a Type Mismatch error whenever we pass a connection object between two vb6 functions. The functions are in different dll's and are sitting in different COM+ packages. Although I've heard that this should not really work (passing connection objectes between components in different packages), it did work perfectly upto a couple of days ago.

Is there any setting on COM+ that I can check or is there something else that could have caused this to start happening?

The fact that it worked upto a short while ago and no code was changed makes me think that it should just be a setting somewhere.... hopefully...