I, too am getting errors trying to run the Exchange Migration Wizard. This happens on both 6.0.8 and also 7.0.0. I am still in testing phase so I can switch between versions pretty easily.
Attached is the ml2 logfile as well as the RPC Error XML file.
Exchange Server is 2003, running on Windows 2003. Workstation is WinXP with Outlook 2007.