If I remember correctly it's almost impossible to uses somebody elses Saves in your Schizm 1 or Schizm 2 game....It takes a lot of explanation to get that right
I think it was Schizm 2 and Sentinel that had that problem -- a "feature" of the Jupiter engine. I didn't bother trying to back up saves from Schizm 2 because it looked like there was an entire save folder for each save and maybe save-related files outside the save folder. Someone at Mystery Manor may have worked it out, but it looked harder to me than any puzzle in the actual game.
The first Schizm had a normal one save file per save, with names such as Schizm.s05, Schizm.s06, etc.
I don't know if the GOG version is compatible with saves from the DVD version.