There is no reason why your 97 files cannot be opened in 2003 (or 2000 or
XP, come to that).
Are you sourcing the file from a server or stand-alone PCs?
Do you still have your old system? Can you still open the file on it?
If we are talking about stand-alone machines ...
What is the file size on your old system?
What is the file size when you copy it to your new system?
How did you transfer the files?