The exe file is most certainly what is called a runtime.
In FMP 5 the version that could create this runtime was called Filemaker Developer ver 5.5
The best bet would be to find the original database that was used to create the runtime,
make the changes, and create a new runtime.
That's the problem David, the original database that was used is nowhere to be found after 7 years, lol.
Thanks for your reply!