Hi again Ted aup (Audacity) files cannot be sent to another PC even one with Audacity. All it is is a shortcut to stuff saved on YOUR pc. So it is impossible for another PC to open a shortcut when the file it is a shorcut for is not there.

http://audacityteam.org/wiki/index.php?title=File_Management_Tips

This link explains more. My advice is to keep each track as a seperate entity saving it individually so you can work on and edit each individually. But keep a mixdown MP3 as a working demo. I save EACH TRACK SEPARATELY as such and such song bass, such and such vocal, such and such piano, etc.