GroupWise client hangs when attaching a file

Windows XP Pro SP3, GroupWise client 8.0.1

I have at least two different machines that will lock up the GroupWise client when attaching files to messages. Exactly as TID 7002246 describes, but without that resolution. The "Send To, GroupWise Recipient" works without issue, and the users can successfully attach files when on other workstations. Uninstalled the client, rebooted, reinstalled the client - problem still exists.