I'm still not convinced you have a compatible set(OS-Pro Tools_Mbox 2 Pro), but I would bet that Sweetwater installed all the software without having an Mbox to connect. With that in mind, I would re-install Pro Tools and when the installer tells you "Connect Interface"; Connect the Mbox, wait about 8 seconds and click Okay(I'm fishing a bit here as LE7 is really old and I have not done an install on a Mac system in years). If that doesn't work, get back on the phone with Sweetwater