The users who are using the third-party Debian Multimedia repository have been advised to stop using it as soon as possible.
The reason for this announcement is that after the Debian Multimedia repository has fallen in disarray, someone has registered the domain and his name is unknown to the good folks from Debian.
“This means that the repository is no longer safe to use, and you should remove the related entries from your sources.list file.
“After all, the need of an external repository for multimedia related packages has been greatly reduced with the release of Wheezy, which features many new and updated codecs and multimedia players,” reads the official announcement on debian.org.
If you don't know if you are using the third-party Debian Multimedia repository, there is a very simple command. Just open a terminal and enter it:
grep debian-multimedia.org /etc/apt/sources.list /etc/apt/sources.list.d/*
If debian-multimedia.org shows up, you really need to remove that repository from your system.