I agree with magicbus: there must be something on your computer, or its settings, that are causing issues.
I'm running FF 45.0.0 and Windows 8.1 and have no problems with CNBC or any other videos.
Almost sounds like you are infected with malware or some sort of browser hijack. My recommendation would be to disconnect from the internet (wireless as well), reboot into safe mode, run system scans with ALL of your protection software to clean infections, and maybe even perform a system restore back to a point where you are confident that everything worked as it should.
The part of your warning that specifies DRM software is required sounds like a phish to get you to click a link or something else that would install more malware -- BE CAUTIOUS!!