Client Crash problem

hi all
i have a problem and i can't solve this issue for about 2 days.

*The problem:-
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when i attack the lion mob (level 111) at jubiter zone after 2 to 5 minutes the client close itself suddenly and i can't relogin again.

after many tries to find the reason of this,i guess that the reason must be an item drops from the mobs because i can relogin again after a moment when item disappears or i can relogin by restarting the whole server.

what i need now is to know where i can find the assigned drop items to a mob in the media text files ?!!

Regards..