ReferenceError: UNLIMITED_CPS is not defined.
You may see this error while using Firefox Throttle.
Firefox Throttle is a very good plugin for you to limit the speed for upload and download with your browser firefox.
You can limit for uploading to youtube or downloading from site and you can use another browser to browse smoothly like IE or Chrome, while you are in low bandwidth places.
To solve this problem, make sure you must check the
1. Throttle download
2. Throttle upload
If you uncheck any of them the error will be displayed.