As I discovered this morning, there is an issue when using Firefox 3 to access Ebrary. Once you have installed the Ebrary Reader, you may find that you have inadvertently wandered into an "install missing plug-ins" loop. If this is the case, don't worry, there is a way out.
Mac: save the plug-in to \Library\Internet Plugins folder on your Macintosh HD
Windows: save the plug-in to My Computer\Local Disk C:\Program Files\Mozilla Firefox\Plugins then restart your browser
This should free you from the loop. If you have any questions, please feel free to contact me.