I will try to explain is as best detail as i can. I have only a couple plugins but i know for a fact that they dont factor in the crash. But what happends everytime is that when a player throws out their pokemon, the server crashes. The pokeball doesnt even have to hit the ground before the server crashes. Also pokeballs (the actual item) will not show up when throwing them, and do not crash the server. It seems only when players throw out pokemon it crashes.
Heres the error: http://pastebin.com/nT44jxdd