http://bugs.winehq.org/show_bug.cgi?id=32451
--- Comment #4 from Alex bigjohnaumic@yahoo.fr 2012-12-15 23:03:01 CST --- Here is a workaround to install the game : use the /nogui option.
WINEPREFIX=/my/wine/prefix wine setup_the_witcher_enhanced_edition_2.0.0.12.exe /nogui