author link

I have just installed wordpress 3 today to test it and something really weird is happening.
I am using the twentyten template that came with wordpress 3, and have only installed W3 Total Cache and WP-DBManager.
What is weird is that the link to author is not working. I have only 2 posts. The original that comes with wordpress instalation and one I created to test.
I tried de-activating both plugins, and the error remains.
Does anyone had this problem? Am I missing something here?
I did not change any of the template files, I have not altered any of the code. It just did not work in the first place.
Any hints to solve this?
The url seems fine – http://mydomain.com/author/authorID, but it gives an error:
“Not found.
Apologies, but the page you requested could not be found. Perhaps searching will help.”
I just don’t understand what is happenning.