Cant install plugin (browser firefox - vista)

[Admins]

By default the Firefox installation on Vista is bugged so that you cannot install any plugins.
You can either add yourself read/write access to the Firefox folder (Program Files/Mozilla Firefox) or install Firefox into your own user folder.
Even when you do that then Graal is not displaying perfectly in Firefox on Vista yet, when you scroll the page then its not scrolling the Graal window, will try to fix that in a later version.