I have the same problem too! I upgraded my wordpress yesterday to 2.0 and had no problem. Then today the nightmare come! The plugin suddenly back to default one and “tinyMCE” error come out! I am not sure it is my web hosting problem or what…. how can I check and fix it? Thank you.
I just try “Hello Dolly” again and it act as expected! However I am not sure other plugin why don’t work..
For example, this one:
http://mudbomb.com/archives/2005/02/02/wysiwyg-plugin-for-wordpress/
and this one:
http://orderedlist.com/articles/wordpress-administration-design-tiger/
and also Hello Dolly,Markdown and Textile 1.
I have tried deactive all other plugin but one in case they interfere each other. But no luck. Thanks!