Can't delete wallpaper.

I just recieved my mac book pro, and was looking for things to spice it up, like cool wallpapers. I found one called EarthDesk, and I downloaded it off of Apples site. Well I figured I would just try it out, but I didn't like it so I tried to switch back to a default wallpaper.

It switched back but after about ten minutes the earthdesk one re-appears. I tried moving it to the trash and deleting it for good, but when I click empty trash it says that earthdesk is still in use.

Does anyone know how I can remove this desktop for good?

It's not just a desktop, it's an application that will auto-update your desktop to display geographical information. Reboot your Mac and it should go away if you've deleted everything..