Unfortunately you'll have to get a version that works with your os which to my knowledge is 10 or 11. Also always make sure your interface is supported with the os and pt version.
(Although since v9 you could work off the computer headphone/line output without any soundcard.)
A simple Google search turned out this:
http://avid.force.com/pkb/articles/e...ility/en419171
http://avid.force.com/pkb/articles/e...m-Requirements