I moved files to itune folder but still not being found??

My itunes wasn't able to find original files over the network(on a diff. computer) so I put them on an external drive. I've dragged this folder of songs, called "music" into the itunes music folder. Now Itunes is set to look here for songs, and in this folder are all the artists listed and my folder music. The problem is when I click in the itunes library to play one of these, the original still can't be found. When I go to the itunes music folder, open my music folder, play a song , it plays in itunes. I don't understand what the problem is. I do see that the songs under artists are all mpeg4 and my songs under music are mp3's. Does this make a difference? It seems like I finally have the files in the spot where itunes looks, but it's still not working. I must be close? Right?

 

From what I know, each song in your playlist has a specific path to its location, down to the last subfolder in your iTunes library. Whenever you play the song, iTunes follows that path to find the song. If the exact location of the original files are changed (for example if you moved the files to another subfolder in your iTunes library or renamed some files), the path must be manually changed to coincide.