Nothing certain, unless it's related to the OutofMemoryError with native threads/thread-stack. I don't know if the answer to your problem is there, but http://wiki.jboss.org/wiki/Wiki.jsp?page=OutOfMemoryExceptions might be helpful.
We are seeing the same error even when we give 2.5 gigs of heap space + 196 Perm space. The wierd part is that jvm is stopping and we have to restart the jboss again.
The same error happend in my application.
The config:java 1.5 , tomcat 5.5
We run application at one computer,when user go up,we add another computer,but the new machine java clash frequently.Two computer is same.
and why? Maybe not the JBoss's mistake,but java's