Im having trouble logging into the Zenworks Agent on any workstation.

ZCM is on a win2003 server and installed successfully. The user source is
set up to access edirectory and I can browse the directory contents and
see the users within the Control Center.

The Agent has been installed manually on the workstation and is registered
under devices in the control center. When I log in to the workstation the
Zenworks login box appears and asks me to enter the user id again which it
then rejects (The system could not log you into the network, bla bla bla).
Both the server and workstation can ping each other by hostname and IP.
The firewall is turned off on the workstation.

If I go into the control center I can see the workstation and its status
is green and I can remote control it.

I have tried it on a clean install of xp and the same thing happens.

Any ideas how to fix this?

Thanks in advance,