Amarok - Musicbrainz tagging doesn't work on ogg files

Hi all. I have been succesfully using amarok for tagging my mp3 files, but it refuses to work on .ogg. The first time i try to tag an .ogg file, it behaves as if it were generating the digital fingerprint for the song, but then it fails saying that there is no information available for that song at MusicBrainz (even for very, very well known songs!) Then, if i try to tag the file again(doesn't matter ifi try to tag that same song or another one), it fails immediately (ie. without even trying to generate the fingerprint) and states that there's no info for that file at MB. Anyone has any ideas of what could be happening? Thank you all, Anderson