I have one iTunes instance (v10.6.0.40) a Windows 7 PC.  I'm having problems copying playlists from there to my Macbook Air's iTunes instance.  Here's what I do:

 1. On the Win7 machine, I right click the Playlist, choose Export, export it as a .m3u8 file, and save it in my Dropbox.
 2. On the MBA, I grab the new playlist from the Dropbox, and drop it into the Mac's iTunes library.

After that, instead of a list of songs from they Playlist, I just get this:

![A blank playlist, I guess?][1]

Which I guess means that the newly imported playlist is blank.  

How can I (successfully) copy playlists between two computers?

  [1]: https://i.sstatic.net/Uk8cA.png