mp3 option and 6.9.3cs1

Hi... I've read all of the online help, and 100s of DUC messages but I still can't figure out what to do. I just bought the mp3 option, and I have 6.9.3cs1 installed. When I try to install the mp3 codec from my 6.9 or 6.9.2 updater I get the error saying that I must have at least version 6.4 installed, and the installer quits. I've never installed the demo before and I don't have the codec anywhere on my computer. Any tips appreciated!

I did that, and I don't have any codecs installed for protools at all. There's not even a folder for them.

I figured it out; I dragged and dropped the mp3 codec from my 6.0 installer cd into my Pro Tools folder on my hard drive. I bypassed the installer altogether. Thanks for the advice though.