http://bugs.winehq.org/show_bug.cgi?id=34060
--- Comment #10 from Tomas Schlosser Schlosser.T@seznam.cz 2013-11-06 02:20:05 CST --- I have found the fix for this if anyone is still experiencing this issue:
Install driconf package and enable S3TC (under Image Quality). Now the ETS2 works just fine. Both windows version under wine and native Linux version from Steam.