Bad text in some games

[WizardStan]

I am currently using 1.6 rc5, but this has been going on for a while.
Basically, sometimes text renders perfectly, and other times it looks like this: http://rebirthofxeen.com/images/Screens ... 20Game.png
It isn't entirely consistent across games. In Treasure Adventure Game above, for example, the introduction is normal, menus are all normal, just the text displayed when you talk to someone or read a sign is messed up in this way. There's been a few other games like this but I didn't pay them much attention. I just got Saira on the Steam Summer Sale and it is similarly afflicted: a lot of text is fine, but then some menus get this weird corruptiness. It makes me think of a unicode problem, but I've tried changing my encoding in several different ways and nothing seemed to make any difference. Is there something I'm missing?
Thank you!

[dimesio]

Have you tried winetricks allfonts?

[WizardStan]

Yes I have.