it`s self explanitory, if you have a font called courier on your system then DB will change to that font and use it for printing and text commands from then onwards, if for some reason the command fails, then it will continue to use the default font, I assume from that that you don`t either have a font called courirer on your system, or for some reason it failed to load or that it was so similar to the font you where already using so you didn`t notice the difference.
Mentor.
PC1: P4 hyperthreading 3ghz, 1gig mem, 2x160gig hd`s, Nvidia FX5900 gfx, 6 way surround sound, PC2: AMD 1.2ghz, 512mb ram, FX5200 ultra gfx, stereo 16 bit soundblaster, ups.