Migrating Exchange 5.5 on a Windows 2000 Server

Has anybody attempted to migrate Exchange 5.5 to exchange 2003 on a separate windows server 2003.
Whenever I attempt to perform DSSScan in “Coexistence with Exchange 5.5” DSSScan has trouble contacting Exchange 5.5. I established a 1 way trust on the 2000 and a two way trust on 2003.
Any help? By the way I am not a graphic design artist.
Thanks,
Vilas