I kept getting "Error during streaming! Reason: Could not retrieve playlist."
Started to make a playlist on LastFM web site, but noticed this statement:
"Subscribers can listen to playlists once they contain at least 45 playable tracks by 15 different artists."
So I click on the "Subscribers" which was highlighted and it looks like you need to pay a fee for mobile streaming.
http://www.last.fm/subscribe
Now I have used the pc in the past for lastfm, and the sound is awesome which I use at home.