[daryn]

I had this problem too, and since it appeared to be crashing in native code, I had a hunch that the native stack size was too small. I was right. Even if that just meant nothing to you, simply launch:

Utilities -> Java -> J2SE 5.0 -> Java Preferences

Add this to the "Java Applet Runtime Parameters":
-Xss10485760

Basically says to give each thread a 10MB stack. It's likely overkill in size, but no more crashes for me!