CSS mystery - bg image stops repeating

When I add a Google search box to the header of a website, the background image of the "outer" div stops repeating about a third of the way down the page, where the inner "container" div ends.

See the blue fade on the left and right of www.portsmouthnh.com/index1.cfm (http://www.portsmouthnh.com/index1.cfm).

What's up with that? I haven't a clue.

Your website is showing MAD errors when i checked it through w3. You might want to consider fixing them, this may fix your problem!

http://validator.w3.org/check?uri=http%3A%2F%2Fwww.portsmouthnh.com%2F&charset=%28detect+automatically%29&doctype=Inline&group=0&user-agent=W3C_Validator%2F1.3