AS3 / Flash CS3 : adding instance name breaks dynamically loaded swf?

Question

Hi, I have managed to dynamically load a swf in AS3 and instantiate one of it's library symbols. Everything was fine until I decided that inside my library symbol, I would give the textfield that was on the stage an instance name, so I could manipulate it after loading the swf.

One thing I noticed was that immediately i added the instance name for the textfield ("txt"), I also had to import the textField class in the movieclip's class, in order to compile.

I can no longer see the textfield in the dynamically loaded swf. I get a runtime error: ReferenceError: Error #1056: Cannot create property txt on Hello (i.e. Error #1056: Cannot create property {textfield-instance-name} on {loaded-swf} )

(Hello is the Class of the loaded swf. For some context, this is a continuation of : http://stackoverflow.com/questions/1766750/)

I just wanted to be able to manipulate things inside the loaded swf...