You are getting this error because of the Neat Digit forum extension (this time digit guys are not to blame

). Due to recent change in the forum the extension is giving error.
I have uploaded the new version (
2.67) of extension, download it from here :
https://addons.mozilla.org/en-US/fir...versions/11096
Also visit this extension thread for updates. The extension will not auto update until its approved by Mozilla. So please download from the link provided.
Neat Digit forum