I had a similar issue in the same place a while back. You might try unchecking the "shiny waters" box in your video settings, or it could be a bad tileset .hak file, but it's probably the first thing.
I disabled shiny water when Slag was level 4 after a concealed snake terminated him in the Windjammers cave :P
Must be the tile set. We got out ok in the end.
It is the tileset. I crash in that area 3 out of every 5 times I take any of my toons there, even with shiny water off and low video settings. I personally try to avoid ever going there because of it. It is a shame because it is beautiful...
Have had the same issue with the same character occur just as Slag entered the Battlehelm Moors with Sibbicai. This time I'm unable to log back in. Something suspect surrounding Sib and Slag in the swamps. Silverblades said that he crashed too but I don't know if he managed to log back in.
Regards,
Eltalstro
Edit: I finally managed to log back in and exited into Dapplegreen. I decided to see if I could go back into the Battlehelm moors without it crashing. Managed to make my way through most of the screen before crashing again.
Re edit: Turned all video option down to lowest and was able to log in fine.