The standard script doesn't actually search, it goes directly to the artist page. If that artist is not on discogs you get 404
So you enter Various, it goes here http://www.discogs.com/artist/Various
To search for an album you can install additional scripts from
/t/1992/1 or
/c/web-sources-scripts
But this album seems to cause some problems with the track titles, you can try this one:
/t/6191/1