i didn't have to
keys 1 thru 9 are my weapons (across the top of my key board) .. are you trying to use the keys on your numpad (the ones on the right side) or the ones across the top of your keyboard
for numpad buttons to work you may need to hit that key on your keyboard to shuts on and off num lock
numlock is enabled by default in your bios settings on many systems
but i dont have any special kind of keyboard just a junk dell one plugged in right now, i beat up my logitech wireless one (gotta replace that)
*EDIT* just tried it numpad keys will not work (might if you configure them ?)
only the numbers over my alphabet keys do , and i prefer mine there so i didn't try to rebind em
1 - 4 are my guns 5 - 0 are throwables and C4 and mines