ADMT Error 7585: Access Denied when migrating users with groups


I am migrating Users & Groups from a 2000 domain to a new 2003 domain (new
forest) using ADMT v.3.
I can happily migrate users and groups seperately, but when I attempt to
update group membership of multiple groups, only the first group in the list
is updated. The process then halts with:
ERR3:7585 The account replicator is unable to continue. Access is denied.

It all works fine if I migrate the groups one at a time, but there are many
groups and this will kill me!

Here is the full log after I attempted to update memberhip of 3 groups
(GBPB, GBS7700 and Gbusiness&Commercial) - only the first in the list was

[Settings Section]
Task: Group Migration (20)
ADMT Console
User: UK-FWL\administrator
Computer: (UK-FSWS001)
Domain: uk.fwl.local (UK-FWL)
OS: Microsoft Windows Server 2003 5.2 (3790) Service Pack 1
Source Domain
DC: (FWL-NT07)
OS: Windows 2000 Server 5.0 (2195) Service Pack 4
Target Domain
Name: uk.fwl.local (UK-FWL)
DC: (UK-FSWS001)
OS: Windows Server 2003 5.2 (3790) Service Pack 1
OU: LDAP://uk.fwl.local/OU=Employees,DC=uk,DC=fwl,DC=local
Intra-Forest: No
Migrate Security Identifiers: Yes
Update Rights: Yes
Fix group membership: Yes
Conflict Option: Merge, rights = No, members = No, move objects = Yes
Migrate members: Yes
Password Option: Generate passwords, only for new objects = Yes
Password File: 'C:\WINDOWS\ADMT\Logs\passwords.txt'
Translate Roaming Profiles: No
Source Disable Option: Leave source account
Source Expiration: Do not expire source account
Target Disable Option: Set target same as source

[Object Migration Section]
2006-06-06 11:28:09 Starting Account Replicator.
2006-06-06 11:28:10 WRN1:7561 ADMT could not migrate some properties for
this object type (group) due to schema mismatches. Please refer to the
Schema Section in the migration log for a complete listing. The Schema
Section will be available once object migration is complete.
2006-06-06 11:28:10 CN=GBPB - Merged.
2006-06-06 11:28:10 SID for FW-LOGISTICS\GBPB added to the SID History of
2006-06-06 11:28:11 CN=GBS7799 - Merged.
2006-06-06 11:28:11 SID for FW-LOGISTICS\GBS7799 added to the SID History of
2006-06-06 11:28:11 CN=GBusiness&Commercial - Merged.
2006-06-06 11:28:11 SID for FW-LOGISTICS\GBusiness&Commercial added to the
SID History of UK-FWL\GBusiness&Commercial
2006-06-06 11:28:11 Processing group membership for CN=GBPB.
2006-06-06 11:28:11 LDAP://\,
Julie,OU=Staff,OU=Employees,DC=uk,DC=fwl,DC=local added.
2006-06-06 11:28:11
LDAP://,OU=Staff,OU=Employees,DC=uk,DC=fwl,DC=local added.
2006-06-06 11:28:12 ERR3:7585 The account replicator is unable to continue.
Access is denied.
2006-06-06 11:28:12 Operation completed.

Thanks in advance for any help.