Apple Logic Pro /LogicExpress Discussion

Hi,
Dumb question time:
I deleted all unused tracks in a mid file song.  I changed my mind and wanted to import 
the audio AIFF mixdown of this mid that I had done and add some more stuff, (without 
having to remix the whole song).
I added an audio track but may have been confused by all the options when you click on 
the track.
I imported the audio file but got the message that "I did not have sufficient priviledges and 
the track would not be saved".  What is the deal with that?

I tried loading the same file into an empty project and it loaded and played fine.  
Hmmmmm.....

Thanks for your help.
Charlie