I had this problem to, i fixed it by going into the config with a text editor and changing
data/config/r3dopengl.cfg go down to the line that says
Video.OpenGL.FontCache.UseMultiTexturing = yes
and change it to
Video.OpenGL.FontCache.UseMultiTexturing = no
that fixed the font mess ups for me, but if you update it changes the file back so you will have to edit it again. Also most of my problems were fixed when i went from the radeon ("ATI") driver to the fglrx driver which you can get through package manager or from ati.com, best to search for a guide on how to install the driver for your distro before doing it tho.