It took me awhile to figure out how to get Exaile works with last.fm. Go to Edit->Preferences and enable the AudioScrobbler plugin by selecting the checkbox. “AudioScrobbler” should now appear under Plugins. Enter your last.fm user name and password and choose http://post.audioscrobbler.com in the drop-down list. Click Apply.
I actually went there to this dialog before but i didn’t notice the plugin’s name somehow :”>