Thank you for the update.

Bob Lin, MS-MVP, MCSE & CNE
Networking, Internet, Routing, VPN Troubleshooting on http://www.ChicagoTech.net
How to Setup Windows, Network, VPN & Remote Access on http://www.HowToNetworking.com
<cody@safetrac.com> wrote in message news:1172810180.386053.136590@p10g2000cwp.googlegr oups.com...
Thanks Robert,

I should have said that the VPN is an IPSEC tunnel between two ADSL
endpoints, they're Impel units, aka linux boxes with ADSL termination.

Thankfully I think I have fixed my own problem.

After doing some digging it was found that the PDC, server A was
having file replication problems.

The main event indicating this was:
"The File Replication Service has detected that the replica set
"DOMAIN SYSTEM VOLUME (SYSVOL SHARE)" is in JRNL_WRAP_ERROR.

Replica set name is : "DOMAIN SYSTEM VOLUME (SYSVOL SHARE)"
Replica root path is : "c:\windows\sysvol\domain"
Replica root volume is : "\\.\C:"
A Replica set hits JRNL_WRAP_ERROR when the record that it is trying
to read from the NTFS USN journal is not found. This can occur because
of one of the following reasons.

[1] Volume "\\.\C:" has been formatted.
[2] The NTFS USN journal on volume "\\.\C:" has been deleted.
[3] The NTFS USN journal on volume "\\.\C:" has been truncated.
Chkdsk can truncate the journal if it finds corrupt entries at the end
of the journal.
[4] File Replication Service was not running on this computer for a
long time.
[5] File Replication Service could not keep up with the rate of Disk
IO activity on "\\.\C:".

Following recovery steps will be taken to automatically recover from
this error state.
[1] At the first poll which will occur in 5 minutes this computer
will be deleted from the replica set.
[2] At the poll following the deletion this computer will be re-added
to the replica set. The re-addition will trigger a full tree sync for
the replica set."

I followed the steps in this on server A, and it worked a treat.

I then restarted the File Replication service on server B, which then
sync'ed the required files.

It worked out that server B was demoted from being a domain
controller, as it's files on the domain system volume had not been
sync'ed in 60 days!

So after doing the sync, I got an event stating that server B had been
reinstated as a domain controller.

I have not tried to add the Vista Business workstation, but I have a
high confidence that it will

Thanks for your assistance Robert!