installing Raw Plugin on PSCS on MAC

Okay, I have the raw plugin for CS on my desktop, but I can't figure out how to install it. The computer simply won't let me for some reason. I'm on Mac and using PSCS. Can anyone help me with this. Sorry if this has been posted before, I made a search but I couldn't find anything--although I never find anything with search.
(Dave, added the MAC to your title so the right people look at it, Glen)
(Dave, added the MAC to your title so the right people look at it, Glen)