I had same exact problem. First did this:

You need to delete all of the MMIDCache files (I believe there are 8 of them, numbered 0-7)
Multimail Disconnect
MultiMail Attachments
MultiMail Messages

Delete these from your backup folder as well.

Then - I installed the update to Outlook conduits from Palmone.com (v1.02)
Then - I turned Versamail in the Hotsync custom to "Do Nothing"

It appears to be working