file found but not found

I'm not sure if this is the right forum, but I'm stuck; so I'd be
grateful for any help. I am trying to use a program called FIAT in
Windows XP. I can open the
program from CD. Then I browse to find the appropriate input file,
which might have the path name D:\FIAT\practice2.inp. So the program
has clearly found this file. When I then do try to open it, the program
says the file cannot be found. How can this be? On one computer, when I
transfer the file to the 'C' drive, the program can then find it, but
on another computer, at the university, it can't, (although it can open
the program all right) giving the same 'Not found' message as I get
using the CD. I think the FIAT program was
written in C++ for Windows 95. Any suggestions?