I tried to use the process above and just lost all my itunes songs. Now in the old location and in the new location I set I just have a folder named "automatically ad to itunes" and no music file. Now my itunes library is empty. What can I do?

The source Mac, if you open itunes, does it still show your itunes media (music/movies/etc), that you're trying to move to the other Mac? And/Or, if you go into your ~/Music folder on the source Mac, do you see an iTunes folder? If you go in there, and look in iTunes Media, do you see your music?

Well, to be honest, the music couldn't have just vanished. It has to be somewhere, unless there was an accident that involved deleting it. I mean, if you have simply copied and pasted from one place to another, it's not going to remove the music.

Try doing a spotlight search for a song that you know existed in your music library. If the spotlight seach shows the song you search for, hold CMD and click the song. That will open it in finder, and you can see where it is located. Maybe that will show you where the rest of your music is.

And if that all fails, and you've done a thorough search and still can't find it, do you have a backup? Like a time machine backup?

Or, where is the music from? iTunes purchase can be redownloaded again.

Btw, I kind of assumed you were moving it from one mac to a different mac. Is this the case or was I mistaken to assume that?