photo/camera app on itouch 4g says rebuilding library then crashes

every time I try to open my photos app on my iPod touch 4g I get the screen 'Updating Library - Please Wait' With a little blue loading bar at the bottom stating 'Rebuilding Library'. When the blue bar gets to about half way of loading the app crashes and goes back to the home screen. It also does exactly the same thing with the camera app. I tried everything, I restarted my iPod, I synced it with iTunes, I restored it from a backup, I tried to delete the last video I took (using the computer, because I can't get to it from the ipod.) and it says you can't delete the video because the device is already in use. what more can I try?