Global Variable Question

hey guys, so, im going through colin moock’s book, “the definitive guide”, and im learning about global variables. so in his lesson he says to do this:

  1. create a movieclip called square, with a square inside of it.

  2. in the square mc’s timeline, on frame 1, place this code :

_global.day = “tuesday”;

  1. go back to the main timeline and on frame one put this code:

trace(day);

no according to moock, when i run the movie, it should output “tuesday”, but all i keep getting is “undefined”.
i’m running mx 2004, so im wondering if that has anything to do with it…any help is appreciated! -daniel