well if you are loading a specific bio.swf out of a specific folder, then you know the folder. So set the folder as a variable when the user clicks that artist's button and use the variable again to load the txt.
I am not expert on loading txt files so maybe someone else can handle that part.
The easiest way is to use XML, but that may be too hard for the artist, although it could be pretty simple XML.
You could also create an Admin flash swf for the artist to go to and fill out their info, then write out the xml from it, and let them edit it, but thats more work for you.