Ok, there's some confusion here. Speaking to OS X specifically...
C3 is required to setup some initial data on OS X. So you must provide the system password to the dialog asking for permission to make changes. Click cancel to that dialog and authorization will not work. Subsequently if you don't allow permission, then silent installers won't work either (they require elevation to run).
However, you don't have to uninstall/reinstall to try to get authorization working. In fact, according to Apple guidelines, we do NOT have any authorization logic in the installers.
As far as authorization, that's handled in a separate process. It's not necessary to have C3 open in order to authorize. So to diagnose demo mode, you need to look at the about box and work with support to give them the code if any that appears. We're working on a newer version of this process to fix the auth issues on 10.7/10.8 so expect things to improve very soon.
There is currently a bug with some of the installers that are not correctly updating the data used by C3 to show the installation state. To get the lights working does not require installation/reinstallation through C3. It's supposed to work whether or not the packs are installed directly through C3 or by running the pkg files directly in the download directory. In fact all C3 does is launch the pkg installers silently.
As far as what's listed in C3? Think of the UI of C3 as a connected download manager/installer. The products that appear are connected products that you own. You will likely own other products that are not listed for a few reasons. 1) it may be for a different platform, we only show OS X products on that os. 2) it may not be a connected product. (Dimension Pro for example). What causes products to appear is purchasing connected products.
We're hard at work addressing serious issues and will roll out an update for the various bits as they are sanctioned by QA.
Thanks for everyone's patience as we work to give you the great experience you deserve.
Best,
Keith Albright
Director of Development