Theme Builder

We are running Theme Builder 3.3.3 on Confluence 2.7.3. Occasionally it's happened that all the themes except the Default theme "vanish" from the Manage Layout screen, as well as any other admin screen - such as the backup and import screen. Yet, the themes are still active for their respective spaces, and everything appears normal otherwise. The problem is, we have to shut down and restart Confluence in order to restore the admin pages to full working order again. Do you know what the problem is? Is there some way to get the themes back in the admin screens without having to restart Confluence?

Thanks!

Brian Kelly