Remove the Alert line
Remove the two getreals and replace with 1 and 0
Are you setting oom somewhere ? else just (setvar 'osmode 47) or your preferred value don't need if.
If you crash it should run again choosing menu.
Oh gosh, I just realized that you are running R12! I though we were working on R13 Good on you man, it is super fun to have a vintage CAD station. If you need some period drawing files, I have a substantial collection of Architectural/Engineering files.
Happy to help.
If you have a Microsoft Mouse, you can find a DOS driver for it here:
https://winworldpc.com/product/microsoft-mouse/9x
If you have a different one, let me know and I will be glad to help you track down a driver.