Hi Buster2008, I had the same problem when I installed my new graphics card.
For days I would ran into an error like this every half hour.
While searching for a solution I learned that there are different possible reasons why I got this error.
As my graphics card was brand new I assumed it was not faulty itself, though at times I doubted this. Checked if my system was overheating and this was not the case.
Ingame I lowered all my graphics settings to safe mode and played the game to see if this error went away. For me it did and next I slowly set my graphics settings to medium, one by one. After each change I would play the game for hours without the error. With everything on medium settings, I started to move them up to high, one by one. Then I hit one that caused the same error. Moved that one back to medium and noted it down.
Although I couldn´t play the game on it´s highest settings anymore, I could play without the error. I finally solved the problem by trying out different graphics card driver versions. Then Nividia released new drivers and I tried those out. Since then I rarely get this error.
I hope this helps.
P.S. You can set the grapchic settings to safe mode, before starting the game, under Tools on the client loader.