On April 2, 2012 the Mozilla Foundation announced that the Firefox browser would start blocking older versions of the Java plug-in from running. Both USPTO’s EFS-Web for Registered filers and Private PAIR use Java.
USPTO recommends that all users of Firefox upgrade to the latest version of Java - which is Version 6 Update 31. Please visit Java.com using your Firefox browser, click on “Free Java Download”, and follow the installation steps provided.
If you do not update Java, it is very likely that when accessing EFS-Web for Registered filers or Private PAIR with Firefox, an error message may appear on the Authentication Page stating: Java Not Enabled.
If you require further assistance, please call the Patent EBC at (866) 217-9197 (toll free) or send an email to EBC@uspto.gov
(Message from the Patent and Trademark Resource Center Program [PTRCP])