but it 'appear's' that we need to install bitcointalk.org's forum software on OUR machines before we can login to bitcointalk.org, is this correct?
These are instructions to install the server software that will in the future run on bitcointalk.org. Forum users will not be required to install anything with the new software.
Note that the software is not yet feature-complete (in particular, the Web design is far from done), and the public repository doesn't contain everything already done.