Loading text from external sources

i can load text, but not so that it will change when a button is clicked (load a different file.)

there are two tutorials on this issue in the tutorial section

http://www.kirupa.com/developer/mx/multiple_dynamictext.htm
http://www.kirupa.com/developer/mx/externaldata.htm

both of which supply final sources and both of which have errors.

Warning Scene=Scene 1, layer=action, frame=1:Line 1: Case-insensitive identifier ‘loadVars’ will obscure built-in object ‘LoadVars’.
loadText = new loadVars();
Total ActionScript Errors: 1 Reported Errors: 1

the loadVars error is in both of them.
what is the answer?
I am using MX2004