I hit this problem and I found that some of my firefox "~/.mozilla/firefox" files have somehow been changed to root ownership. Changing them back to my userid and group fixed the problem.
awr wrote, On 10/20/09 07:51: > Thanks > > The solutions provided by Mozilla: > 1) Exit other programs: There aren't any, this happens every time I reboot. > 2) Exit Firefox: Exit, restart, same problem. > 3) Check for incompatible extensions: Uninstalled all. Same result. > 4) Check if Norton360 installed: Obviously not. > > 5) Delete places.sqlite, bookmarks.json and localstore.rdf > > I don't know where these files are located. they're not in /usr/lib/firefox. > Where can i find them? > When you run firefox it creates your profile in your home directory under .mozilla.