Start Firefox in Safe Mode {web Link} by holding down the <Shift>
(Mac Options) key, and then starting Firefox. Is the problem still there?

Bookmark and use this; Download the Mozilla Search Reset {web link} This add-on is very simple: on installation, it backs up and then resets your search preferences and home page to their default values, and then uninstalls itself. This affects the search bar, URL bar searches, and the home page.

Note that Firefox uses the "chrome://" protocol to access its own internal files and also access files from extensions (no relation with Google Chrome).

• https://developer.mozilla.org/en/Chrome

The alotabgen in the name of the URI usually gives a clue about the (broken) extension that is causing the error.

• chrome://alotabgen/content/alottb-widgetWinError.html