I’ve had problem with color names ever since around the time I’ve upgraded to Xorg 7.0
This problem as been annoying, but it was acceptable, just until lately.
I’ve discovered that a required file /etc/X11/rgb.txt was involved, and was required for X to understand color mappings.
For some reason, although x11-common 7.0.20 was supposed to have this file inside, it did not ("apt-get install –reinstall x11-common" left the directory without the rgb.txt file). It seems as if this package is somehow broken (saw same effect on x11-common 7.0.22), so I’m attaching my rgb.txt here, for your convenience. rgb.txt
Note that in order for changes to take place, you must restart your X when done.