That is an error being caused by a malfunction in an Extension ('''''Add-ons > Extensions''''') named '''''bandwidthmeter'''''. You need to go to the site where you downloaded that extension (maybe your ISP), try to locate the name of the developer, and contact the developer for a solution. That extension is not produced by Mozilla. If it is this extension - [https://addons.mozilla.org/en-US/firefox/addon/bandwidth-meter-and-diagnostic/ Bandwidth Meter and Diagnostics] - from the Firefox Add-ons site, go to the '''Website''' shown on that page for assistance. '''If this reply solves your problem, please click "Solved It" next to this reply when <u>signed-in</u> to the forum.''' ---------------------------- Not related to your question, but... You need to update some plug-ins: *Plug-in check: https://www-trunk.stage.mozilla.com/en-US/plugincheck/ *Adobe Shockwave for Director Netscape plug-in: [https://support.mozilla.com/en-US/kb/Using%20the%20Shockwave%20plugin%20with%20Firefox#w_installing-shockwave Installing ('''''or Updating''''') the Shockwave plugin with Firefox] *Next Generation Java Plug-in for Mozilla browsers: [https://support.mozilla.com/en-US/kb/Using%20the%20Java%20plugin%20with%20Firefox#w_installing-or-updating-java Installing or Updating Java in Firefox]