Using a different browser or just downloading the game itself should solve the problem.I'm assuming you're on a mac, so an alternative would be to go into\<your name>\Applications\Utilities\Keychain Access\ and see if there is a note in it telling to automatically deny a java applet with that signature.
I was going to play Minecraft on Saari and then i accsedently denyed the Applet permession thingWhat do i do?
didn't work