I think it's in B Minor. I don't really know anything about the Dorian Mode, since I only know songs, except by whether they're in Major or Minor key. [Someone corrected me by saying that Papa is in Eb Dorian, but it's really in Ebm b/c it has 6 flats in the key signature.] But I think you have a point about the Dorian mode b/c it seems to me that it's a cross between F#m, A Major, and Bm. I just got an idea; if you can't really tell what key a song is in, then it's most likely in Dorian mode.