If you happen to be running Assistant on Firefox, which I do because I prefer the experience, please note Firefox currently defaults to having the Java plugin disabled, and when you make your menu selection you will either see a pop-up on the display that asks if you want to activate Java or a little flashing icon up on the alert bar that you have to click on the first time to activate the plugin.
Internet Explorer could be having Java issues as well, but that one likes to throw up scary certificate messages and you have to hit the I don't care button and then it keeps the location bar red the whole rest of the time....