Two things to try.....
Right click the LW icon and go to Properties>Compatibility. There you change the compatibility mode to Windows NT (or Windows 2000)
If that doen't do the trick, uninstall LW and all Java versions on your system. Reboot and then download the JRE offline installer of the newest Java version from here:
http://java.sun.com/j2se/1.5.0/download.jsp
Install it and reboot again, then reinstall LW.