Very Basic Question About Pro Tools And Dae Options

[MacNewbie]

Hi,

I bought a used Mac recently and it has Pro Tools 6.0 on it -- but when I try to start it up it says I have to put a DAE in my Systems folder. I have never used this software and would love to play around with it, but I have no idea where the owner before me got Pro Tools or if she ever bought a special card, etc.

Do I need an audio card to be able to run ProTools?
Do I need a special Digidesign Audio Engine -- and is so, where do I get it, assuming I already have some working version of 6.0 on my HD?

THANKS!