You should check how much space you have in rootfs (256MB partition), and in home partition (2GB partition). Having a little space in both these could cause serious problems.

Media player is more associated withthe home partition. The tracker process won't start unless there is approx >50MB free. This is a good place to start to solve this issue. Install conky and see how much space you have. If you have less than 50MB uninstall a big app / game. You should have more space now.

In xterm write: tracker-processes -r
or install trackercfg.