Mac Forum / Applications / Excel / July 2006

I'm having a recurring problem with a couple of the Names that I'm trying to
define.  

I have an excel Workbook that contains several different worksheets.  I'm
trying to create a hyperlink from a cell on one worksheet to a cell on
another worksheet.  I'm created and defined the names for many of the cells
already--"A", "B", etc--all the way to Z.  These are the names because it's
a listing of books by their Alphabetical difficulty level.  (Every book has
a level denoted by A-Z).

I've successfully defined names (and then easily hyperlinked to them) for
all but two letters.  Consistently the "C" and "R" cells will not let me
define their names.  It keeps saying "That name is not valid".  I'm doing
absolutely nothing different for these two than I did any other letter.  The
only way that I could get it to work is by defining them as "C_" and "R_".

Any idea why these two won't work the correct way?

Running Office 2004 (latest update with exception of the 5th.)  Working on a
G4 Powerbook with OS 10.3.9.