Re: The problem probably wasn't the software...
> Fortran is a well defined language with widespread compiler support.
Not really. FORTRAN written in 1989 is likely a sludgy mixture of what the F77 Standard said it should be plus a collection of vendor-specific FORTRAN extensions that are unportable from one FORTRAN compiler vendor to another.
Back then, the notion of code portability between compilers wasn't on anyone's mind. Vendor-specific non-portable extensions were considered cool.
FORTRAN in all caps because that's the correct spelling of the official name of the language.