You already seem to be running the latest Firefox 8.0.1 release according to your System Details, so why are you trying to update?

my FFox browser has a message that "you are not running the lastest version of FFox.. pls update .."

The text about not running the latest Firefox version is in the code of the www.google.com/firefox site that previous Firefox 3 versions use as the home page and Google doesn't seem to maintain that page anymore.
Current Firefox 4+ versions no longer use that Google site as the home page, but use the build-in about:home page as the home page.
Google assumes that you use an older Firefox version if you still visit that site and warns you that you use an older Firefox version and suggests to update.
You can use another page as the home page like about:home or www.google.com or www.google.com/ig (iGoogle).

You can update to Firefox 9.0.1 if you want (not sure if there is an automatic update offered for Mac users).

• http://www.mozilla.com/en-US/firefox/9.0.1/releasenotes/
• Firefox 9.0.x: http://www.mozilla.com/en-US/firefox/all.html