Hey folks, i have just completed my first java aplet game based on the old arkanoid 'not again',lol, anyways the game runs fine on my laptop which has ME and the 1.4 sdk/jdk blah blah blah installed yet when i run it on my desktop it wont start and if it does runs VERY slow, my desktop is a 1.4gig and my laptop is a p2 366, im doing this as part of second year at uni and am quite new to java, anyways here is the error from the debugger.

Set uncaught java.lang.Throwable
Set deferred uncaught java.lang.Throwable
VM Started: java.security.AccessControlException: access denied (java.lang.RuntimePermission modifyThreadGroup)
at java.security.AccessControlContext.checkPermission(AccessControlContext.java:270)
at java.security.AccessController.checkPermission(AccessController.java:401)
at java.lang.SecurityManager.checkPermission(SecurityManager.java:542)
at sun.applet.AppletSecurity.checkAccess(AppletSecurity.java:169)
at java.lang.ThreadGroup.checkAccess(ThreadGroup.java:287)
at java.lang.Thread.init(Thread.java:286)
at java.lang.Thread.<init>(Thread.java:332)
at JBreak.init(JBreak.java:48)
at sun.applet.AppletPanel.run(AppletPanel.java:347)
at java.lang.Thread.run(Thread.java:536)

and im getting a null pointer exception when the paint method is trying to paint the graphics, anyone spot whats wrong without me posting the whole code,lol,any help would be great thanks