Lynaria, have you tried to reïnstall the client? So first deïnstall the one you use now and download the client from website again and install it on your computer.
I hope this would solve it for you. If not then I am out of options too =(
well I tried your suggestion again Vanadey and today it worked as was able to battle without it freezing when I won. But now after I do win and get out of a battle the server freezes when I try to open something else. This happened in multi dungeon when came time to collect after killing the final boss. Waited 5 minutes before reloading.