Automatically Update to 3.0 is Not Automatically Updating to 3.0?

Hi,

I am trying to update my site (http://4.biz) to WordPress MU 3.0.

When I press the "Uprgrade Automatically" button, it looks as though it has started and gives me the message "Downloading update from http://wordpress.org/wordpress-mu-3.0.zip."

However, nothing happens after this.

I don't really want to do it manually as I am not confident enough that I won't mess my entire site up!

Please help!