A Google search turned up some ideas for dealing with this error. It is sometimes referred to as a bug, but is generally considered to be an error code. The official reply from Aspyr's technical support reads :
This is Aspyr technical reply after all this game time with NO problem, it's your graphics card.
Thank you for contacting us. Unfortunately, your machine does not meet the requirements for the game. The game requires one of the following video cards (also listed on the back of the box):
ATI Radeon 9800
ATI Radeon X300
ATI Radeon X550
ATI Radeon X600
ATI Radeon X700
ATI Radeon X850
ATI Radeon X1300
ATI Radeon X1600
ATI Radeon X1800
ATI Radeon X1900
nVidia Geforce PCX 5900
nVidia Geforce FX 5950
nVidia Geforce 6200
nVidia Geforce 6500
nVidia Geforce 6600
nVidia Geforce 6800
nVidia Geforce 7300
nVidia Geforce 7800
nVidia Geforce 7900
We are unable to provide support for machines that do not meet the minimum requirements for the game.
I then found this item from a user :
What fixed my problem "where's the guru" error - my direct3D acceleration somehow got disabled.
run dxdiag through start run
tab display
check the DirectX feature buttons and make sure all are enabled:
DirectDraw Acceleration
Direct3D Acceleration
AGP Acceleration
The standard answer to this question on other fora is to patch the game.
#1 : Gothic 3 OFFICAL patch 1.2
#2 : Gothic 3 UNoffical patch aka Official Community patch 1.6 (2008-02-07)
Some people find that reducing graphical overhead (turn off ground cover, etc.) helps, some find it irrelevant.