So, not only /etc/X11/rgb.txt was missing, Jaunty seems to have created a symlink to that unexisting location (someone please confirm, it could have been me, by mistake, while trying some solution).
Anyway, copying /usr/share/emacs/22.2/etc/rgb.txt to /etc/X11 solved it. Thanks!
Bug #358678 indeed seems to have the same root cause. Here's something interesting. Before the workaround I had this:
$ locate rgb.txt X11/rgb. txt X11/rgb. txt emacs/22. 2/etc/rgb. txt X11/rgb. txt X11/rgb. txt -> /etc/X11/rgb.txt
/usr/lib/
/usr/share/
/usr/share/
$ ls -l /usr/lib/
lrwxrwxrwx 1 root root 16 2009-04-27 17:57 /usr/lib/
So, not only /etc/X11/rgb.txt was missing, Jaunty seems to have created a symlink to that unexisting location (someone please confirm, it could have been me, by mistake, while trying some solution).
Anyway, copying /usr/share/ emacs/22. 2/etc/rgb. txt to /etc/X11 solved it. Thanks!
Z