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

Start Firefox in Diagnose Firefox issues using Troubleshoot Mode 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.