Vlookup help please

[Korimint]

Why does this formula create and #N/A

=IF($A8="","",VLOOKUP($A8,'What needs made'!$C$2:$H$36,4,0))

But this one does not

=IF($A8="","",VLOOKUP($A8,'What needs made'!$C$2:$H$36,5,0))

Both are looking up a zero total, the second formula returns a zero, the first formula returns a "Blank space"

Do I have a formating error? Both are formated to be Numbers.

So confused!!

I am using excel 2010 & Windows 7

Thanks for the help!

 

[Korimint]

=IF($A8="","",LOOKUP(9.99999999999999E+307,CHOOSE({1,2},0,
    VLOOKUP($A8,'What needs made'!$C$2:$H$36,4,0)))

Thanks Aladin!!