The version used in the show is the "Saeed & Palash Remix". It has been released on multiple releases of "At The End". The song is 9:38 minutos long.
"The Scumfrog Remix" is the version that has been used in the megamix on the soundtrack release for season 3. That version has received quite a bit mais play in clubes and is considered por many to be the best remix of the song, even at the time when it came out, which is why I guess it was used instead. Either that or it might be due to licensing issues which is why several songs had different versions featured on the various soundtrack releases of the show.
I've embedded a video of the remix below. Feel free to compare it to the scene in the show which I'll link here:
link They edited a bit for the show though.
