Vlookup second column if first is empty not working

Struggling with what I'm doing wrong. http://www.excelforum.com/images/smilies/cool.gif

I have a Vlookup to a sheet within my workbook. What I need is if column 27 is empty, I need it to return the answer in column 20. What's happening is that it will find column 20....but if there is a number in column 27, it returns 0.

Help please.

=IF(ISERROR(VLOOKUP(A2,'GOVT W FRT'!A:AD,27,0)),"0",VLOOKUP(A2,'GOVT W FRT'!A:AD,20,FALSE))

Try this assuming the expected result of the vlookup is numeric (both columns 20 and 27)

=LOOKUP(9.99999999999999E+307,VLOOKUP(A2,'GOVT W FRT'!A:AD,{20,27},0))

Thanks Ace!