I also have the problem that I cannot get the rich text editor to work (it does not show) neither on http://demo.opensourcecms.com/wordpress or on my own site. I’ve tried IE7, FF2 and to turn off my own anti-virus.
I don’t see the visual edit buttons. I’ve enabled them under ‘Users’. When writing a post I get an error in IE7 saying that “tinyMCE” is undefined. It is the same with Firefox. I tried to upload ‘wp-includes’ once again (with SmartFTP) but that did not help. I’ve not previously installed WordPress before I installed 2.1. Does anybody have an idea to what I can do?