Just an experiment if I may:

1. Set Java to 1.5 ___ Java preferences for Leopard ___ (the order I have it set at seems to work, but may require some experimentation for yourself.)

2. Delete your LW prefs folder; Deleting LW Preferences folder in OSX

3. Set up a new account & see if same problem occurs; Setting up a Test Account in OSX (click on link)