it is essetial that the names in the flash movie match 100% with the variable names you use in PHP. This includes capitalization.
If you use a movieclip inside of your movie, you have to include the complete path to the text components, or better, use the LoadVars component for communication.
The tutorial shows the basic functionality. Before you start enhancing it, you should make it run as it was, to make sure the environment works.
Then start modifying it step by step, until you understand the functionality and the dependencies of the components and functions.