http://bugs.winehq.org/show_bug.cgi?id=23443
--- Comment #4 from Dmitry Timoshkov dmitry@codeweavers.com 2010-06-30 23:09:35 --- (In reply to comment #3)
I'm not sure how to find it out. Changing fonts in the Desktop Integration/Appearance/Items doesn't seems to affect the one used by Wine in message boxes. Could you please tell me how to find it out? Right now I only can say that I'm using stock fonts + winetricks corefonts & tahoma.
The Font choose dialog uses "MS Shell Dlg" font which should map to Tahoma. Are you using Wine Tahoma? Does the problem persist with empty ~/.wine?