Package: gnome-desktop-data
Version: 2.22.3-1
The binary package gnome-desktop-data doesn't contains OMF files  
corresponding to {gpl,lgpl,fdl}.xml files. Therefore, the various  
links like "ghelp:gpl" in Yelp generate an error message.
I suspect you have to add .../usr/share/omf in gnome-desktop-data.install