If you provide more information with how you dc maybe I or someone else can help you. There are some problems with this old version of MapleStory and there are fixes for it. Usually you need to GFX, you can't boss when using MAC, Nvidia graphic cards are a problem too.
I think that was the problem. My first two runs I was using windows 98 compatibility and did not use GFX. I recently had a successful run using windows 7 compatibility and GFX.