Thanks for spotting the error on the slipping expressions tip, I fixed that this morning.
The expressions tutorials work for me (IE 5.1, Mac OSX) and have been previously tested on several platforms and browsers. They are large files and take a while to download and as I am in Las Vegas on a dial up connection I cannot do extensive testing today. I will retest when I return home. One other thought, perhaps you need the quicktime plug-in installed for your browser????