er in Ubuntu Hardy Heron ===
You need to add the following lines to /etc/apt/sources.list file or you need t... tc/apt/sources.list</code>
Make sure you have the following two lines save and exit your file
<code>deb http:... niverse multiverse</code>
Now you need to run the following command to update the source list
<code>sudo apt-get update</code>
Install mplayer using the following command
<code>sudo apt-get install mplayer</code>