When entering information to submit a new release, clicking "enter edit" throws the following error and prevents the release from being submitted:

unknown Label id: at lib/MusicBrainz/Server/Controller/WS/js/Edit.pm line 380, <$fh> line 1

I suspect the label (Mercury) of this particular release is not in the Musicbrainz database. Rather than throwing an error, it would seem to be better to add the label until the release can be verified and voted.