hello drobertson, you're using firefox 21 which is the latest version. the message you're seeing is probably just showing up, because you're using google.com/firefox as one of your homepages, which was only maintained until firefox 3 and now shows the warning message you've referred to no matter what browser version you're using. change the homepage to about:home in order to address the issue & to get the current firefox homepage...

How to set the home page

Hello,

The Reset Firefox feature can fix many issues by restoring Firefox to its factory default state while saving your essential information. Note: This will cause you to lose any Extensions, Open websites, and some Preferences.

To Reset Firefox do the following:

1. Go to Firefox > Help > Troubleshooting Information.
2. Click the "Reset Firefox" button.
3. Firefox will close and reset. After Firefox is done, it will show a window with the information that is imported. Click Finish.
4. Firefox will open with all factory defaults applied.

Further information can be found in the Refresh Firefox - reset add-ons and settings article.

Did this fix your problems? Please report back to us!

Thank you.

To be more clearer on philipp said about Firefox start page. The http://google.com/firefox was in use up til Firefox 4.0 was released (3.6.28 was last to use it) as it was changed to about:home since.

Thank You very much to Philipp, tylerdowner and james foir your responses. They all contributed to my ability to sort out the problem and get back to normalcy. Appreciate the timely and informative responses.