Three words, perhaps..
"Service Pack 2"?
I haven't tried running any of my trunker-type software on XP since I installed SP2, but it has given me grief with some other software. (Minor stuff, y'know, like Windows Explorer CRASHING when trying to view folders.)
If you have recently installed SP2, it might possibly be the cause. Or if you selected "Automatic Downloads" in the SP2 harassment screens.
Then again, XP is not exactly renowned for its DOS abilities anyway..
Wish I could be of more help...
[EDIT: Looking at your screencap again, have you created a shortcut for Trunker? What happens if you try to run it directly, either from Explorer or a command prompt? You may have to build a new shortcut... maybe something (*cough*SP2) has corrupted or made unusable the existing shortcut.) Also, AUTOEXEC.NT is a file kind of like the AUTOEXEC.BAT on the DOS boxen of old, but for NT (and XP) to allow DOS compatibility in a Command Prompt window. (CP is not a DOS shell in XP, like it was in previous Windows versions.)]