Solved: Formula error

[Emoncada]

Can someone tell me why im getting a #n/a error with this formula

=IF($J$812="","",IF(VLOOKUP($J$812,'[PCAR Orders & Inventory- testing.xls]ORDERS'!$A$4:$C$5000,3,FALSE)=$D$812,"","No Match"))

I am trying to do this
I would like to look at $J$812 and if the cell is blank then leave as is.
If the cell has something I want it to do a Vlookup and if the vlookup finds a match then if the 3rd column of the match is = to $D$812 then leave blank otherwise if it doesn't find a Match Or it doesn't = $D$812 then give me a "No Match".

Hope that explains what I am looking for.

Any Ideas?

[Bob Phillips]

=IF($J$812="","",IF(ISNA(VLOOKUP($J$812,'[PCAR Orders & Inventory-testing.xls]ORDERS'!$A$4:$C$5000,3,FALSE)),"",
IF(VLOOKUP($J$812,'[PCAR Orders & Inventory-testing.xls]ORDERS'!$A$4:$C$5000,3,FALSE)=$D$812,"","No Match")))

Just like I said at MrExcel.

[Emoncada]

ok this works

=IF($J$812="","",IF(ISNA(VLOOKUP($J$812,'[PCAR Orders & Inventory- testing.xls]ORDERS'!$A$4:$C$5000,3,FALSE)),"No Match",
IF(VLOOKUP($J$812,'[PCAR Orders & Inventory- testing.xls]ORDERS'!$A$4:$C$5000,3,FALSE)=$D$812,"","No Match")))

Thanks xld for your help.