Description of problem:

When having only the xvfb server installed (ie, not an Xorg server), the xvfb
server cannot open the "fixed" font.

So I'm assuming the package is missing some requires.

Filing the bug for completeness, as the reply may very well be "so just install
everything else then" :) But I wanted to install this machine to not have X and
just run a test suite for a gtk-using application.