Code looping through files

Excel XP & Win XP
I'm helping an OP with a project. The code loops through all the files in a
folder, opens each, does things, closes the file and opens the next file,
etc.
The code is placed in the Personal.xls file. It works fine for me. It
fails on opening the first file for him (will not open the file). An error
is produced saying that opening the file failed. He has Excel 2003.
He sent me his Personal.xls file. I changed the name and put it in my
XLSTART folder. It works fine with my path. I created his path on my
computer and that works fine too.
I checked the VBE - Tools - References. The only thing I have checked that
he doesn't is "Microsoft Forms 2.0 Object Library". He doesn't have
anything like that to check.
Does anyone have any ideas of what I could do? Thanks for your time. Otto


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