[Two client Issue]

I've been running dual client since the game came out, then suddenly out of the blue my 2nd client disconnected while playing and when I tried to restart it, it told me that my graphics card is out of date. I updated everything using avast driver updater, but still I cant run dual client. Now I can only run 1 client at a time and its a real bummer, because I enjoyed having 2 at once. If any1 could help I would greatly appreciate it. The image I attached is the message I get when trying to run my 2nd client.

[RE: Disable Dual Client]

Please dont remove dual client.... Legit makes the game 10X more fun. I'll fall asleep playing my cleric on single client.