How can I get media keys working on my keyboard? [closed]

Try the following; consider them as different tests.

  1. Run showkey (will perhaps require root privileges). This application will tell you if your key is being read or ignored by the system.
  2. Install and run dconf-editor. Go to org.gnome.settings-daemon.plugins.media-keys and set next to XF86AudioNext and prev to XF86AudioPrev.