I recently went through this with Camerabits support and Kirk. Doing a search in this forum should bring up the conversation between Kirk and I. The solution for me was going back to PM5.
PM6 wouldn't connect to my ISP. Got a protocol error message every time. Asked Kirk if addresses for groups would need to be entered as multiple individuals if I ever got PM6 email working with my ISP. He confirmed that they would. He did say I could take a snapshot to save a group in PM6. For me, that would mean maintaining multiple email groups, one in my email app and "snapshots" in PM6. The easiest route for me was going back to PM5. I pick the images to email and PM5 opens an email in my default app where I can use the address book to pick recipients and the text area to enter a message.
Kirk may jump in to correct something I've said in error but I believe the information is correct.
Oh, I'm using Windows Pro 64 bit version 2004.