Fonts are stored by default in something like /usr/local/Trolltech/your-qt-sdk-version/lib/fonts, depending on the structure of your SDK directory when you make'd the source.

Clearly, you can run against the Qt libs, so just try mkdir fonts/ in your Qt lib directory and dump the fonts there (or symlink it to your preferred userspace directory).

Qt Embedded supports TrueType fonts (.ttf), so perhaps copy something familiar like Arial onto your device and specify that. In my experience, not specifying fonts yielded exactly the same issues you're suffering from.

And obviously check permissions, turn it on and off again blah blah blah.

DaRab.