I'd still say it was a mismatched text/number thing.

Make sure you format both cells (the lookup value and the cell in the table that
matches!) and then reenter the value in both locations -- it's not enough to
just reformat the cell.

Debra Dalgleish has lots of notes on troubleshooting =vlookup():
http://contextures.com/xlFunctions02.html#Trouble

Nain wrote:

Hello
I need help. The formula listed below works for all the employee numbers on
my spreadsheet which are in column B except for the employee number 63023. I
tried to convert this number to a text, general, number, reentered it on
another row and spreadsheet and it does not work; instead I get a zero value.
The only time it works is when I key it in as €˜63023. Why does it work for
all other 4 or 5 digit numbers and not 63023?

=IF(ISNA(VLOOKUP(B260,Sheet1!$B$5:$H$290,COLUMNS(S heet1!$B:$H),FALSE))=TRUE,0,VLOOKUP(B260,Sheet1!$B $5:$H$290,COLUMNS(Sheet1!$B:$H),FALSE))

--

Dave Peterson