I found the problem

You only get an Error in PvP because youve run out of energy but itll tell you you havent if youve crashed. Its a glitch, I insist buying Dragon gear for infinite Energy in the game :) the crashes happen when you equip to fast or equip 1 after another. I love Adventure Quests Worlds thats why I purchased this game

Tonnallee about Battle Gems (AdventureQuest), v1.1.4