I am trying to figure out why sumproduct is suddenly returning #value!

At JE McGimpsey's suggestion, I have been using the following formula
as a double check on a spread sheet
=SUMPRODUCT(ROUND($F$63:$F$549*L63:L549,0)), it was working
wonderfully
this double-checks the sum of column M, which contains
=ROUND((F108*L108),0)
Column F & Column L have several text headers within the range. When
I use Tools/Formula Auditing/Evaluate formula, the #value! error
occurs at those text headers. The odd thing is, the spreadsheets I
was using in Office XP had the exact same info, and didn't have an
error when encountering text. I would just go back to the old
spreadsheet, but it is corrupted. Excel help said to move all the old
data into a new 2003 workbook.

http://support.microsoft.com/kb/820712/en-us

Now sumproduct is returning #value!. What am I doing wrong?