IF Statement Doesn't Seem to be Working

I have numeric fields in a table of employee absence data as follows ...

Abs.late
Abs.absent
Abs.early

I have written an error-checking IF statement that doesn't seem to be working, but yet, VFP does not generate an error on it either.

IF Abs.late=0 AND Abs.absent=0 AND Abs.early=0
     MESSAGEBOX('You need to make a non-zero entry') + CHR(13) + ;
          'in either Late:, Absent:, or Early:', 0+48+0, 'Error')

Even if the fields Late, Absent, & Early contain zeros (0.00), this MESSAGEBOX never gets processed, the program just goes right on as if everything is fine.

Need help. TIA, CH.