no pop-up now playing problem

so on other people's computers, whenever you pause or fast forward to a new track, a pop up window comes from last.fm showing all the information on what's currently playing. Mine doesn't do that. please help.

I have the application running, and i believe i'm doing everything correct. I'm on mac with the latest versions of OS, itunes and Last.fm scrobbler

I figured it out. It's a different app completely different from Last.fm. It's called GrowlTunes and you can install it from the Mac App store for $1.99.