This can be a problem with the Babylon toolbar (extension).

Start Firefox in Use Troubleshoot Mode in Firefox to check if one of the extensions is causing the problem (switch to the DEFAULT theme: Firefox (Tools) > Add-ons > Appearance/Themes).

• Don't make any changes on the Safe mode start window.
• https://support.mozilla.com/kb/Safe+Mode

• https://support.mozilla.com/kb/Troubleshooting+extensions+and+themes

[ I've solve ] Well, I was too upset from the errors of babylon, sometimes it didn't allowed me to browse internet and oftentimes it ruined my new(default) tab opening parameters, so finally after damn research i figured it out how to get rid from these errors.; these files (software /errors) weren't visible anywhere e.g. control panel, system32 etc. i got em from C:\......, then i deleted em and got a complete calm. so here you go and remove both things;

C:\Program Files\Mozilla Firefox\searchplugins (bbyln.dll).

C:\Program Files\Mozilla Firefox\extensions (bbyln folder)

after to remove (babylon) relevant files restart your Mozilla firefox. WAIT. WAIT. don't forget to complement me...just say loudly....Well done dude, You're Genius ....O_o....!!!!

Sure, it'd be helpful because its not me its my experience talking to you.