ADMT migration problems

Hello,

I've a serious problem when using ADMTv2 in my migration scenario.

I am migrating my NT4 and Windows 2000 domain accounts and groups in a
Windows 2003 domain. Everything went fine.
But now I encountered the problem that the group memberships of the
user accounts I am migrating are not fixed any more. The user account
is migrated with SID and everything but the group memberships were not.
The log says that the user is migrated but there was no error message
for the group fixing issue. When I activate the option "Migrate
associated user groups" and activate "Update previously migrated
objects" the log says that the groups already exists and were not
migrated a second time. But the user object itself is not fixed.

I checked nearly every setting ADMT requires and everthing seemes to be
fine. All groups and users were migrated with this ADMTv2 installation.

Does anyone have a clue? What setting may I check for this issue?

Regards
S.P.