If you have install 3.6.26 version, your user agent is corrupted by Ant.com Toolbar, because your user agent tell us that you have 3.0.5 version Mozilla/5.0 (Macintosh; U; PPC Mac OS X 10.4; en-US; rv:1.9.2.26) Gecko/20120128 Firefox/3.0.5, Ant.com Toolbar 1.1)

see how to fix user agent: in Websites or add-ons incorrectly report incompatible browser find Reset your user agent and follow the steps.

delete also the Ant.com Toolbar to solve the problem

thank you

Please mark "Solved" the answer that really solve the problem, to help others with a similar problem.

Also do not download the new 10.0 version because it is not compatible with your mac ppc 10.4 os, see : https://support.mozilla.org/en-US/questions/917314

thanks again

Thanks. I reset the version per the instructions. It may have solved the problems. No crashes yet.

I have never heard of ant.com or their toolbar. Any more info on that?

further info:

If I type "ant.com" in the about:config filter I do see that the browser.search.defaultenginename is set to ant.com. I don't know where that came from. It isn't in the list of search engines that I use that is available in the Firefox toolbar. I've never heard of it. Maybe I should change it to something like google.com?

That pref should have the Name of the search engine (Google) as listed in Manage Search Engines (Right-click the search engine icon on the Navigation Toolbar) and not a website URL.

Open the about:config page via the location bar and do a search for ant.com via the Filter at the top of the about:config page.
Reset all ant.com related prefs that appear bold (user set) via the right-click context menu to their default values.

You may need to switch the search engines to get the proper behavior.

• https://support.mozilla.org/kb/Search+bar