Excel 2007 : trouble adding an additional IF function

I have the following formula that works:
=IF($C2=" ","",IF($D2=0,$V$5,IF(VLOOKUP($U2,'Stock on Posting Date'!$A$1:$J$600,9,FALSE)<$D2,$V$3,IF(AND(VLOOKUP($U2,'Stock on Posting Date'!$A$1:$J$600,9,FALSE)>=$D2,VLOOKUP($U2,'Stock on Posting Date'!$A$1:$J$600,7,FALSE)>VLOOKUP($U2,'Stock on Posting Date'!$A$1:$J$600,9,FALSE)),$V$8,$V$5))))

When I add an additional if statement at the beginning it stops calculating after the first if function.
here is the formula:
=IF(VLOOKUP($C3,'Planner Known Issues_CFLi'!A2:J36,1,FALSE)=$C3,CFLi!$V$2,IF($C3=" ","",IF($D3=0,$V$5,IF(VLOOKUP($U3,'Stock on Posting Date'!$A$1:$J$600,9,FALSE)<$D3,$V$3,IF(AND(VLOOKUP($U3,'Stock on Posting Date'!$A$1:$J$600,9,FALSE)>=$D3,VLOOKUP($U3,'Stock on Posting Date'!$A$1:$J$600,7,FALSE)>VLOOKUP($U3,'Stock on Posting Date'!$A$1:$J$600,9,FALSE)),$V$8,$V$5)))))

In bold is the only part of the formula that calculates. Any ideas on why this is happening?

I also need a final function that returns "x" if #N/A