I have seen like 5 different solutions, none worked for me, but they did for some people.
So I can't really say how to fix it :S
I can only share my solution:
I have changed my run.bat to:
start javaw.exe -Xms256m -Xmx512m -jar haven.jar moltke.seatribe.se -r ./res
And then I copied javaw.exe from my java dir into the dir with the game and run.bat file