I apologize ahead of time for the lack of information here, but im hoping theres a somewhat easy answer to this problem.

I am trying to run a 1988 CAD program under dosbox, as it doesnt work properly anywhere else so far, other than a true dos environment. The newest configuration we got it to run on is a Windows 98 environment, started in "dos" using the F5 keystroke on startup.

This program is called Drafix CAD Ultra, and it includes 2 versions of the executable, dfx.exe, and dfxp.exe. (dfxp.exe enables extended memory support).

I am able to run the non-extended version dfx.exe with a default dosbox 0.74 configuration, but the extended version always gives the error "Exit to error: JMP Illegal Descriptor Type 1". I tried tweaking the various options for CPU type, speed, memory emulation, processor type, sound, etc to see if I could get it to run, but the "Exit to error: JMP Illegal Descriptor Type 1", seems to persist regardless. Ive tried doing it on multiple machines with widely varying hardware configurations, but all running Windows XP Pro SP2 or SP3, and the same error appears on all of them.

Has anyone else run into this issue, and is there a known fix for it? A google search turned up next to nothing.