Alright, here is something you should know from back when I developed my own GM compiler: Don't use .save files. You can't save user code that way, you'll run into multiple problems when trying to make an exe and it is just a bad habit. Use .ini files, encrypt them and have a password to open them. .ini files allow you to save a user variable, while a .save file ends all execute strings when saved, then getting rid of all the code the dude typed in and screwing with the resources s/he had.
Plus, imagine all the hell you'll have to go through trying to make that go into another compiler.
This really is nothing more then an interface and saving test, you couldn't use any basic functions, couldn't compile, etc but I do admire you for trying it.
I'd also like to note that when saving, if you click cancel, no string is returned, then giving me an error. I suggest you have a break off from the original code if no string is returned.