Call class method within sub movieclip

programming flash
1

I’m working in Flash CS3. I’ve set my Document class named Main and in the constructor I create my own config class:

var config:Configuration = new Configuration();

and I set a variable named TEST:

config.TEST = "hello world";

When I trace the property on the main Timeline it succeeds, but when I’m doing the trace() from within a MovieClip on the Timeline, it failes with the following error:

1120: Access of undefined property config.

What am I doing wrong, or what is proper way to do this?