Comment 1 for bug 314123

I struggled with this issue for a while as well, and managed to figure out what was going on. The solutions is to create a skins directory in /var/lib/bugzilla3 - the path for the FlatGreen skin is /var/lib/bugzilla3/skins/contrib/FlatGreen. It appears to me that the problem is that the package does not create the empty directory, and there is no bugzilla (in the Debian readme or otherwise) that explains which skins directory the additional skins should be placed in.