Can not remove post from top navigation

I’ve just installed a new theme; wootheme canvas.

I also upgraded to 3.0.1.

I had a problem with a new page being redirected to the homepage which I solved by deleting the redirect plugin that I wasn’t really using anyway.

Now I can not delete a page that was previously there before the theme install, that I no longer need.

I’ve the solution that has worked before, shown in below link, but it doesn’t work. Any ideas?

http://en.forums.wordpress.com/topic/another-cant-delete-page-problem