When trying to add the Webupd8 Rhythmbox PPA to my system through
sudo add-apt-repository ppa:webupd8/rhythmbox
the command seems to work fine. Then i apt-get update and upgrade, and it shows no upgrade to be found. When i run
sudo add-apt-repository -r ppa:webupd8/rhythmbox
right afterward, it tells me it does not exist in any sources.list files.
Does anybody know what is going on?

P.S. - I have a ton of PPAs on my system. Is this part of the problem?