That you have used, accidentally, the offline installer was a wise decision. You should always use the offline installer of any program, if possible.
I assume you've also used the online installer of Java, or even not updated Java before installing LW.
My adivce: Go and get the JRE offline installer from the newest Java version:
http://java.sun.com/j2se/1.5.0/download.jsp
The uninstall all Java, and LW and reboot. The install Java and reboot again. Finally, install LW.
It could be possible that you have to uninstall your Norton before (though you can try first without uninstalling Norton). As I have read somewhere, Norton sometimes behaves strang with programs installed after the Norton installation.
