I have discovered my test computer (winxpsp2, joined to the domain) and now I am trying to deploy the agent to it via a deployment task. I have entered the correct credentials (domain administator) but the task keeps failing with an error of "credential invalid". I have used those exact same credentials on the zen10 server to map a drive to the test computer admin$ share but it will not work through the deployment task. This is making me crazy. I have even specifically added the domain administrator to the local administrators group on my test computer but I still get the same error.

File and print sharing is on, and exempted through the sp2 firewall.
Simple file sharing is off.
The domain is joined.

I have tried the following variations of the credentials with no success:
domain\domain admin
local computer name\local admin
domain admin
domain admin@domain

Any ideas?