Why didn't iTunes copy from PC to iMac work?

I tried copying from my PC's itunes to my iMac using an external hard drive as the intermediary and it did not work. Followed the Apple instructions to the letter. Even though all data and folders were placed in the iTunes folder on the iMac, when I opened the iMac's iTunes, nothing showed up. No playlists, no music. Old music was still there even though I had removed it via the folders. Made sure iTunes was pointing to the correct folder too, but no luck. What gives?

Running OS X 10.8.4 iTUnes 11.0.4