Java applets do not have permission to execute arbitrary programs. Do allow such a thing would be an error by the program executing the Java applet. So you need to find a bug in "the" Java interpreter (there are many) that is being used. This is a way of saying "you can't do this."
No one has posted to this discussion for at least three months. Please let old threads die and do not reply to them unless you feel you have something new and valuable to contribute that absolutely must be added to make the discussion complete. Otherwise, please start a new thread in this forum instead.