I don't have a solid answer for you on this.. maybe you should email WGT. Sounds to me like there is some sort of conflict with Java coding which WGT servers don't trust or wish to admit. Are you using any additional programs when trying to access the game client?
I would recommend that you run a thorough AV (anti-virus) scan of your system and re-install if need be. That's a rare message and i'n my diagnosis probably means that you're unwittingly funked up or doing something that you shouldn't be.