On my UK disc, the lyrics are absent but the instrumental bits are still there. I've noticed the subs start a bit before, but the subs for this series as a whole were poorly timed with songs anyway.
If it was a rights problem, wouldn't they have recorded their own song for the dub? I remember Gundam SEED did that quite a bit.
EDIT:
Okays, I loaded up episode 41 where the song is also played. In that episode, as I expected, new dub lyrics are recorded. However, even when watching it Japanese audio and English subs, there are no subtitles for the song. The French dub only uses an instrumental, so it's most likely a rights reason.
EDIT 2: I've noticed that there are two subtitle tracks for English (and 2 for French) - the first one has the lyrics for the songs but not the dialogue, the second has the dialogue but not song lyrics (only found out while playing on my laptop).