Seems this Article is out of date, when using 10.7?
The step-by-step does not follow iTunes 10.7. No big deal. I stumbeled through, but the article should be updated by Apple.
iMac, OS X Mountain Lion (10.8.2), iTunes 10.7 (21) 64-bit
What exactly were you trying to do? I hope you weren't trying to move your library because that's not what that article tells you to do.