From what i read on the official cabal forums (EU) it appears that Error Code 6 *** is due to the connection (as Dark Eye Chakra said already). When your connection lags/ you spam a skill as an MP pot is used or otherwise end up with 2 actions that try to send/receive data the server (or the client) scrambles them slightly.
Thus, the server (being a very hateful thing), doen't ask for the data to be re-sent (which would in turn make the server several steps behind you) but instead DCs you!
So, if you are spamming your skills while switching targets insanely fast (aka, using a bot) your more likely to DC!
Using CabalRider, if you have Extra Large Inventory on you will also DC... probably for the same reason!
So.. i dont think it has much to do with your video card drivers