NWPreferred,
Does the remote host have a LANDesk mirror driver installed? You can check this under your systems hardware manager -> graphics cards.
One thing to try would be to disable it and reboot if it is there and then try again. It may be conflicting with the current video driver. You could also try adding the mirror driver if you do not have it.
Another thing that I have found on the Macintosh side at least is that sometimes adjusting the bandwidth setting will spark the video to life.
As for troubleshooting steps in general:
How to Troubleshoot Remote Control issues
Remote control logs:
What log files are used for Remote Control Troubleshooting?
Hope this helps,
Peter