I cant play MP3's

When i start Rhythmbox, I drag some mp3 files from my desk top top to the "playlist" (Im assuming thats what I call it) and I will click the song to play and I get an error code saying Playback Error The GStreamer plugins to decode "MP3" files cannot be found. I went to reinstall the program and looked to see if their were any extra plugins that I could install but it didn't fix the problem. I have no problem playing them in VLC but I was interested in using Rhythmbox so I can have a playlist. So I ask you what the hell is going on, why wouldn't a Rhythmbox come with a Mp3 decoder plugin included and is their an easy way to fix this. If not is their an alternative program I can use that works more like winamp dose for windows? Thank you for the help.