Firefox won't start: file /content/browser.xul cannot be found
 

Ok, another problem with Firefox just appeared out of nowhere (i.e. I have no idea what caused it). When I try to start Firefox, it tells me:

The file /content/browser.xul cannot be found. Please check the location and try again.

?? It started just fine ten minutes ago, and I haven't made any changes to Firefox since then!

Anyone know what might be causing this?

-n.

Try moving (or renaming) your old profile (the hidden .firefox folder in your home) out of the way then restart it.

The hidden directory created is .phoenix; I renamed it and tried to start again. Firefox gave the same error, and there was a new directory created in home called .phoenix. Reinstalling Firefox (via rpms) does nothing to fix this.

When it gives me this error, I've noticed that Firefox doesn't actually quit; ps -A | grep firefox shows:

4043 pts/1 00:00:01 firefox-bin

After killing firefox-bin and restarting Firefox, I get the same error again. Sigh.

(Konqueror still works (which is how I'm posting this), but when programs go boom for apparently no reason, it alarms me. Plus, Firefox owns Konqueror.) Any help appreciated!