He Rene, I've just tried this on the 6-Pack system and get the same error that you get. I know that doesn't answer your question, but does show that it is repeatable.
I'll have a dig around and see if I can find anything - although I've not worked on DOS since 1985. I was a VM Sysyprog from 1980 to 2004 - so VM (and assembler) is my real background.
I'll post back if I find anything.
Simon Knights
UK.
