Parece que los chicos de Canonical no han configurado bien el QT4 :S
http://ubuntuforums.org/showthread.php?t=547868&page=2
Solución que propone, aunque me parece demasiado rollo:
That works for QT4 for me. However after carefully examining, it turns out to be not helpful at OOo.
Just try put something wrong (e.g. a mismatch tag) in ~/.fonts.conf and start qtconfig-qt4 from a terminal,
If qt4 respect your ~/.fonts.conf ,then it will complain something is wrong with the file.
If it doesn't, check in your /etc/fonts/fonts.conf and /etc/fonts/conf.d whether
~/.fonts.conf
If you are sure qt4 respect ~/.fonts.conf,
perhaps you also need to add some lines about hinting in your ~/.fonts.conf to make hinting completely work.
rgb
true
hintfull
If this also doesn't work, your should check whether your entire /etc/fonts/ directory is messed up, if you ever made tweaks in that directory.
I am using a different distribution(Fedora) so it is also possible that my workaround won't work for you since there should be some differences in system-wide configurations.