I googled a program to limit the amount of memory that a program will see Windows reporting, and I could only find
this, which may work, but I'm not certain. (It's a utility for editing certain parameters in programs, they were using it to remove a 2GB cap from a program, not limit the program to 2GB, but honestly I don't know if you can fix it using that, but regardless, if you don't know what you are doing, or even if you do, make a backup of the FS1 file before you edit it!!)
EDIT: I should point out, FSPort is the most logical choice.

Oh, and, the GOG version should work just fine, so if you can find whatever they tweaked on that, it should work.