vlookup error

i used vlookup in my spreadsheet, but doesnt work ...

case: i have a column a of 151 vehicle number , now i have to find principal outstanding from two column b & c table containing 196 vehicle number with principal outstanding , as i insert formula of =vlookup(a1,b1:c196,2,false) and it gives the desired result but then the problem occurs whhen i drageed formula, the dragged formula also dragged the table_array cell (like in a9,b9:c207,false), and when the vehicle number is store before the table_array it shows #N/A, i.e. if a9 contain vehicle number x and if x is at b4, then formula doesnt work...

pl help