Pokemon Black ROM Crashing from use of move

everytime I use moves like Leer or Tail whip, the game Crashs. other moves so far are fine so far (although i've not got far in), but is there a fix to this? I'm using no$GBA
Post Merge: [time]1297886624[/time]
A bit more info, this only seems to happen when your pokemon attacks first with the move, when they attack second, the crash does not happen. This might seem like a little thing, but again, I have no idea what other moves this might cause, and since it restarts the save file to a very early save, it's a bit of a pain.

http://forum.romulation.net/index.php?topic=49789.msg1227227#msg1227227