Wordpress promotional page and page displaying error. (2 problems)

Wordpress promotional page and page displaying error. (2 problems)

I have 2 quick problems. One, on the website I have made, there is an
error popping up and i don't know why. Maybe someone here knows how to fix
it. http://loseitforlifeslo.com/how-it-works/ You can see at the top of
the page there is some unwanted text.
My second problem is trying to get a promo page on the website. I want to
make a simple html/css page that displays a current promotional ad, then
they can click through to the website. I haven't found plugins that do
this, and I don't know how to easily create an html page and add it to the
website.
Thanks for any help! Much appreciated