ZFD 6.5sp2 on NW.

TS app that works fine on 99% of the machines here doesn't work so well on
the other 1%. It's always the same 1% of machines.

TS app icon shows up on the end-user's desktop 100% of the time, the user
clicks to open it, pass-thru authenication works like a champ, then the app
window is about 150x150 pixels...the rest of the full-screen application is
black and completely unusable. I've cleared the NAL cache on the machines
where this has happened to no avail.

The same users log into a different machine and the app works as expected.

There's no rhyme nor reason to what type of computers it's happening
on...some wired, some wireless, some remote offices, some on the local LAN.
All computers running WinXP SP2 fully patched with ZFD6.5sp2.

Googling was no help and I couldn't find any similar posts here about this.

Any clues would be a big help.