A slight update to the Add-on(s) Disabled by Firefox post from earlier this year. Gecko 2.0 added the file extensions.sqlite to the ‘extensions’ files. Firefox 4.0 and newer include this particular file. We have updated the Wiki to reflect these changes. To get your add-ons working again:

• Close Firefox
• Locate your profile folder
• Delete the following files from your profile folder.
  Note: You may not have all these files:
  • extensions.ini
  • extensions.cache
  • extensions.rdf
  • extensions.sqlite
• Restart Firefox

When you restart Firefox it will automatically rebuilt the extensions list, replacing the files you just removed with fresh updated copies. Your add-ons should now be enabled. This method also works in Firefox as well.