Contacts from AD Migration preventing Exch2k3 Migration

[smugg]

We migrated from NT40 to AD2000 about a year ago. Half-way through the first
attempt we had to role the migration back (we had selected a single name
domain foo instead of foo.local-don't do that) to its origianl state. Users
were migrated along with most servers but the roll-back appeared to work.

Our second attempt at the migration went smoothly, so we thought. The user
accounts involved in the migration now have a "Contact" in the users
container. We just assumed it was there as a placeholder for Exch5.5 and the
ADC so we didn't think much of them.

This weekend we tried to migrate to Echange 2003. We followed the steps to
the letter but, when moving mailboxes, only new users moved. Users from the
AD migration failed. It seems the Exchange is trying to use the contact
instead of the user account for the move. We've rolled back the Exchange
2003 migration and are now back to square one.

What are theses conatiners? How do I get rid of them (if I delete them, the
mailbox in Exchange5.5 is deleted so that's not an option)? Has anyone run
into this?

Thanks.