Are you trying to do an exact match and is your search range going to be the same in each of the formuals you use?
if you want an exact match, you current formula becomes the below (added a ,0 at the end)
=VLOOKUP("x",E10:F13,2, 0)
if you want the range of cells to be the same if you copy this formula down it becomes the below (added $ signs to stop the range changing as you copy the formula
=VLOOKUP("x",$E$10:$F$13,2,0)
Now to your errors, Depending on your version of Excel try the below
=iferror(VLOOKUP("x",$E$10:$F$13,2, 0),0)
or
=IF(ISERROR(VLOOKUP("x",$E$10:$F$13,2,0)),0,VLOOKUP("x",$E$10:$F$13,2,0))