Firefox CCK FAQS
Why aren't my bookmarks added?
Because the CCK can't detect whether or not the bookmarks have been added, we need a way to prevent bookmarks from being added every time the browser is started. To do this, we set a preference that we have been initialized and then the bookmarks aren't added again. If you are testing your implementation, you need to reset this preference and your bookmarks will be added. Use about:config and search on cck. The preference is of the form cck.XXX.initialized where XXX is your Company Identifier. Just right click and toggle this preference and the next time you start the browser, your bookmarks will be added.
How do I install a global extension?
Typically people install extensions interactively and they are then installed into their user directory. For something like the CCK, you want to install it as a global extension. Global extensions are stored in the extensions directory where binary is located. To install a system extension, run Firefox with this syntax:
firefox -install-global-extension mycck.xpi
This will cause the extension to be installed as a global extension.