Lunaris temple problem, disconnection

I searched the forum for a solution to my problem but i couldnt find anything. When i am in the level 3 of Lunaris Temple (actually i have reached the final boss) the game stops and then takes me to the account screen.

I am running the game in "medium" default graphics, even i included in the .exe file "client" this "-gc2" (I found this solution on the forum, but does not work).

Sorry for my english :)