I have tested the Sales Demo and Twitter tutorials and they both fail in Chrome and Safari (with Wine). I'm on Ubuntu 10.10.
The Sales Demo contains an empty unordered list [UL]. No categories are shown.
The Twitter app doesn't even show the iphone background in either browser. It has a waiting message and then is just blank. However, the app works perfectly on the tutorial page hosted on your web server.
Could there be an interference because I already have apache running on my machine at localhost:80?
For best results, use the Firefox browser..