Stolen'd
Yes, Tatsu Takahashi stole this song and put it on Newgrounds. While you aren't trying to take credit for it, you are still kinda doing the same thing (when you submit music to Newgrounds you must confirm that you own the copyright, which you don't) otherwise foolish Flash developers will use it and may get in trouble.
I suggest you take this down.
... it is a great song though!