sign the applet, use doprivileged and trust the applet when you open it.
Use htmlconverter in jdk/bin folder to convert you applet so it uses
object tag instead of applet so IE won't try to run it with msjvm.
Signing applets:
http://forum.java.sun.com/thread.jsp?forum=63&thread=524815
second post and reply 18 for the java class file using doprivileged
Still problems?
A Full trace might help us out:
http://forum.java.sun.com/thread.jspa?threadID=656028