Looks like I am having this same issue. Can not stay in game for more than a minute or two and then I crash.

The first time I crashed I was attacking the Bomb Barron NM in Cassiopiea Hallows. Had the "Error (30002)". Tried logging back in and got a message that said the server was down due to maintenance, which I know was not true.

Second time I logged back in and was dead from the NM, returned to crystal and crashed and got the same error.

Third time, logged back in, returned back to Ul'dah. Crashed in the Market Wards and got the same "Error (30002)".