Setting bounty too high maybe? Try something low then work your way up. Maybe there is a restriction on the amount.
Don't have the game so you will need to play around with the values yourself. Look at the current values then set all showing digits to 9 ( 1000 to 9999 ), if it takes, add another digit ( 99999 ), rinse and repeat.
You can lock the values in the editor. Probably best not to do that