Hi... It seems like both of my audio player got above issue when playing m4a files which is Apple lossless. Below are the error warning:
Playing error : Your GStreamer installation is missing a plug-in. at /usr/bin/../share/gmusicbrowser/gmusicbrowser_gstreamer-0.10.pm line 137.
Your GStreamer installation is missing a plug-in.
However I can play those files with VLC but I prefer to use VLC for video only and independant audio player. I did try some workaround or fix such as removing gstreamer-0.10 etc and remove or rename the registry.x86_64.bin but no success. And yep, I installed ubuntu restricted extras.
Ubuntu 14.04 x64
Dual boot Windows 8.1