Error message: "Java Plug-in for Netsacape Navigator should not be used in Microsoft IE. Please use Java Plug-in for Microsoft IE instead."
I'm not real sure WHY this is happening, but after a couple hours of screwing around with this I'm gettin' pretty frustrated. I've been reading up, and one suggestion was that it is a problem with having the "User Agent Switcher" plugin installed.
PLEASE, someone give me a potential solution if you have one. I'd go back to the older version, but I can't seem to find a copy to download.
What user-agent is your Firefox configured to use in about:config? Look for the setting called "general.useragent.override". If it is not present, then Firefoz should be identifying as Firefox. Otherwise, it will show the user-agent string that it is using. If it's set to IE, I suppose it might fool the Java plugin.
Did you remove your previous version of Firefox? If not, try that. All of your bookmarks and settings (profile) will be retained, even if you remove the program. Your profile data is kept in Windows/Application Data/Mozilla/Firefox/Profiles, separate from the folder where Firefox is installed. So you can "completely remove" Firefox without losing them. The new version will pick them up as it installs.