Shared Music Folder is not organized into Media Folders

Hi;

I have an old Mac Power PC G5 that has 2 itunes accounts on it. Because of this we set up a shared music folder where all the content is stored.

Now I am trying to move the music files to an external HD and then to a new mac mini - I am doing this so as to avoid migrating our total user acct and applications ....

A couple questions..

1) I notice that the shared music folder is not "organized" into various media folder ( movies, audiobooks, etc) even though those options are checked off in the preferences in both user accounts - any idea why this is and if i set up the same set up in our new mac how to correct this?

2) Audio book files- some of the folders are audiobooks with (.aa files) and as they are mixed in , it seems I cannot just copy them over and the copying process stalls--any suggestions how to fix

Alternate suggestion- I basically just want to move our music over without moving all our applications etc--is there an easier way ( I should say I only have 1 monitor so that might make migration difficult?)

Thanks for any advice or suggestions

Mac