Excel 2003, XP SP3:
I have written VBA code to define a private Boolean function for my current
workbook and inserted it in a new module belonging to that workbook. VBE
clearly recognizes it and does not flag any errors.

But when I reference the function in a formula (spelled correctly with
upper-case letters where appropriate) the spelling gets altered and the cell
shows #VALUE! When I try to debug the code, there is no evidence that it has
been entered at all.

I have previously tried creating the function under a different name and
placed it in other modules in other workbooks (in my XLSTART folder), but I
had no more success. In some of the tests, the cell value showed as #NAME?
instead.

What am I doing or not doing?