http://tinyurl.com/47h8lb

Using Excel 2003 in WIN XP
Link above has a pic of part of the spreadsheet showing errors

Simple formula adding cells returns a #value! error.
If I just enter 0.00 in each cell referenced in the formula, the error
is solved (as in row 22. How can I set the options so that if a cell is
just missing amounts, the formula will still work correctly?
I could fill in 0.00 in empty cells, but there are roughly 1500 rows of
data............
TIA
Doug