1) This song is not Japanese. The lyrics, obviously, are in English, and the group that produced it is Swedish.
2) This version was not in DDR Second Mix, or any other Konami-produced DDR game.
3) Please don't say "The DDR version," because there are at least two different versions in DDR games: the original in Dance Dance Revolution (1st mix) and the Upswing Mix in DDR Extreme. If you look on the song's Wikipedia page, you'll see that there are at least 20 different mixes of this song.
This is definately not off the 2nd Mix. I have the OST sitting in front of me, and it's not on there. However, I'm looking through the DDR songlist, and it doesn't actually appear to be on any DDR, so where is this from? One of smile.dk's albums?