Help Installing PT 7.1.1 on my macbook

[mikesaysyes]

okay so first off-this macbook is about 2 minutes from going through my window....sigh

okay so my wife got me PT 7.1 a couple of years ago and the computer I had at the time (PC) was crappy so I finally just got a macbook pro (OS 10.6.8) and I was just using garage band and then I remembered the PT so I go to install it.
everything was working fine until I start it up and when I do it says "session must be an audio record volume" so I did some googling and went to workspace within PT and tried change the "T" to "R" and it wouldn't do it for the Mac HD but I also read that you don't want to record to the system drive anway-
So I went and purchased a 1 TB OWC Mercury Elite AL Pro External FW Hard Drive- but the same thing happened-it would not let me change the "T" to the "R"-I read that I need to deleted the digidesign db's and the preferences but to no avail-

if anybody might be able to help I would be eternally grateful

macbook pro 10.6.8
4 GBS of RAM
Pro Tools M-Powered 7.1 updated to 7.1.1

Model Name: MacBook Pro
Model Identifier: MacBookPro8,2
Processor Name: Intel Core i7
Processor Speed: 2 GHz
Number of Processors: 1
Total Number of Cores: 4
L2 Cache (per Core): 256 KB
L3 Cache: 6 MB
Memory: 4 GB
SMC Version (system): 1.69f1
Sudden Motion Sensor:
State: Enabled