Ok, i've been posting today about the following formula, which was giving me
a "VALUE!" error. We figured out that it was because one of the cells had a
space in it. But once i went in and took the space out (so there is a value
in the more current date's cell but no value in the older date's cell), it is
now giving me an answer of 1293 for the difference between the two cells.

=IF(AD2133="","",IF(DATEDIF(Z2133,AD2133,"m")=0,"" ,DATEDIF(Z2133,AD2133,"m")))

AD2133 has a value of 2007-10-10 and Z2133 is blank