I have a formula I've successfully used in a spreadsheet for over seven
years in the USA (spanning multiple users and Excel versions). A group
in Belgium is now trying to use it, and getting an "Error in formula"
error. They have the exact same computer set up we use (Excel 2003),
yet the formula doesn't work over there. They have tried on several
machines.

Anyone know why this might be? Or any debugging strategies? Any insight
or guesses at all?

Details...

Where SerArea is named dynamic named range in column A.
Where LetIdNum is a named cell (value is "D")

The variable syntax is this:

=COUNTIF(SerArea,INDIRECT(LetIdNum&ROW()))1

That gets the error when entering it ONLY in Belgium.

Without variables, it would evaluate to this simple syntax:

=COUNTIF(A1:A18,D2)1

Funny thing, when entered in that simple format in Belgium, it WORKS.

Then, in Belgium, we replace a constant for a variable and it still
works:

=COUNTIF(A1:A18,INDIRECT(LetIdNum&ROW()))1

Then, in Belgium, we replace the last constant to a variable and it
still works:

=COUNTIF(SerArea,INDIRECT(LetIdNum&ROW()))1

Guess what? NOW, it's been edited back to the original syntax it
refused to accept before. It threw an error when we put it in directly
like that, but when we put it in as simple syntax and then edit it to
this it works. Is that crazy or what?

Any helpful comments would be great because I need the variable version
of the syntax to work like it has here in the States for so many years.

Thanks,
Chuck