My Firefox was working fine, and now I just changed the settings (History) to delete all the data once, I closed the browser as default and installed LinkExtend, WOT and SecretAgent plugins, and Firefox is showing me an error message. I have reset the settings back and disabled the extensions, but still its showing an alert message for each page load(atleast once it'll show for each page load, sometimes it may exceed to 2 (or) 3. Here, I've given the link for my problem : https://dl.dropboxusercontent.com/u/76460759/Firefox_Error.png . Any here suggest me how to solve this issue.