Unfortunately, HP appears to have fallen far behind in support for this add-on. Many people have reported luck in manually changing the compatibility setting in the extension. It involves multiple steps, but it isn't that hard. First, make a backup of your computer for safekeeping. To back up Firefox, see [https://support.mozilla.com/en-US/kb/Backing+up+your+information Backing up your information]. Next, check out this article: [http://pdileepa.wordpress.com/2009/06/30/digitalpersona-4-and-firefox-3-5/ DigitalPersona 4 and Firefox 3.5 « VolatileChar]. Note that some helpful people may have edited the extension and reposted it. Because you really have no idea whether you can trust these edited versions, it's probably worth the time to edit it yourself. Does it help?