wine users - Nov 2008 - Re: Google Sketchup 6.x works, but only with xserver-xgl.

So, you have Intel graphics?  Which chipset?  I hear the 915 isn't good
enough
for sketchup, but the 945 might be, though you may have to disable DRI. 
See  http://wiki.winehq.org/GoogleSketchup for more info, look at the links
section at the bottom.