My Rythm box player cannot play mp3 and iget this error "GStreamer extra plugins cannot be installed on your computer type (i386)

Either the application requires special hardware features or the vendor decided to not support your computer type" if i go to software center i get this error

The repository may no longer be available or could not be contacted because of network problems. If available an older version of the failed index will be used. Otherwise the repository will be ignored. Check your network connection and ensure the repository address in the preferences is correct. in shot i have tried to dowload deb softs i still get the error above .so i have downloaded tar.gz and i have installed using terminal but i get another error of gcc c++ insanity check failure! i ask my self what i am supposed to do nothing is working nothing at all yet i have to run my bussiness help urgently before i collapse and choose to die!