Program Error

[Roger R]

I have a worksheet that I created with many macros and
formulas with in it. Some of the people who are using
these worksheets are on Macs and are unable to use the
macros, which I have worked around. The mac users are
entering data into the worksheet then sending it back to
me. Some work fine, but others have been generating a
Program error with this message:

--excel.exe has generated errors and will be closed by
--Windows. You will need to restart the program.

--An error log is being created.

This message is followed by excel shutting down without
saving anything, which is very handy.

Any help would be greatly appreciated.

Roger