Micro Focus Cobol programs don’t work in vDos. The XM DOS extender is special in its kind. Whereas other DOS extenders switch from protected to real mode to call BIOS functions, XM implements its own protected mode BIOS, that then ‘messes’ with the real BIOS data.
I downloaded your program, but - as expected - only get a “RET from illegal descriptor type 12” exception.
“unhandled call” entries are not uncommon in vDos, mostly it’s just the program probing what’s present/supported by the PC/OS. Int 2F – 9600 is undocumented, probably only MF will know what it’s intended to do. Main issue could be the “OpenFile failed: FELIX\PROG\FELIX.DLE(2)”. It is not present, but could be optional.
I know vDosPlus ‘fixed’ the "RET from illegal descriptor type 12" exception. But that was like fixing a division by zero: Pretend it just didn’t happen, w/o addressing the actual cause. The XM DOS extender is a nasty thing, and seemingly requires a high level of compatibility with real hardware.