For some reason this doesn't work:

=VLOOKUP(a4,[VFW_Cell_Dept_Matrix.xls]Sheet1!$A:$B,2,false)


** The cell doesn't even get treated as a formula inside it....


Do you mean that the ar cell ref doesn't resolve the A4 when you hit Enter?
Does the false resolve to FALSE? What does it return in the cell? #N/A! ?
#VALUE! ?