Maplestory Crashes 20-60 seconds after i log in - Why?

I run a 64-bit Vista with 6GB RAM dual core processor and 600GB HD space (i think 313GB left) and have never had this problem before. However, now, whenever i log into the game, I have enough time to go to the jesters room and get onto the top left plat - But whenever i use slashstorm, MS crashes. I don't know if its random or anything, but its really annoying. Its not just once or twice - i've loaded the game about 8 times now and the same thing keeps happening, + or - a few seconds. Does anyone know why this is happening? or how i can stop it?