Pokemon tap error. it crashes when there's a pokemon.

im trying on a new hack on fire red.. but i got a new problem. for some reason the pokemon tap crashes to black when i try to enter it. i can still hear the music but its just black and i can't go back to the menu. i thought it was something to do with the set flag but it only crashes when there's apokemon in it. when i literally have no pokemon and i set the tap it works just fine even though i have no pokemon! i really have no idea what is happening is any rom hacking pro got to this problem before? if so please help.