why exactely do i need an ASPI layer?

[Sublime_4_Life]

My question is exactely how the heading states...why do i need one? I have a laptop and my internal cd-rw works just fine and i also have an external dvd burner (Pioneer S606) that work flawlessly. But when trying to use clonyxxl it says i need one installed...I used adaptec's aspi checker and it says i dont have one at all? So why do i need one to backup games or the like? Sorry its kindof a dumb question but i just have no idea cause everything seems to be working fine without it...
Btw im running Windows XP

ps - adaptec's website is sucking and i cant seem to download the aspi layer anyways...does anyone have another link to it i could use?

THanks