dropbox show error 404 on *.html

I want to put the HTML5 game on dropbox, but about my *.html files says, that it was not found.

I did everything according to a lesson from Ashley, but it does not work.

Here's an example:

index.html and test.txt located in the same folder Public / Test on the dropbox server.

Public links:

dl.dropbox.com/u/50581036/Test/test.txt - that's ok

dl.dropbox.com/u/50581036/Test/index.html - error 404

What am I doing wrong?