GrooveWalrus for Ubuntu is a music player that features GrooveShark and Last.fm support. If you are having problems with things not working as well as you think they should, you might want to run GrooveWalrus as Administrator. That is right-click the GrooveWalrus icon on your desktop and select Run as Administrator.
What's new in version 0.382
Version 0.382 has fixed issue with pre-fetching and options.