bbPress.org

With layout issues like that, it’s nearly always a div issue (div size, float, unclosed, extra, something.) So, you should validate first:

http://validator.w3.org/check?verbose=1&uri=http://www.supporttheanimals.co.uk/bbpress/topic.php?id=3

Can’t validate because of an invalid character on line 8. I tried to view the source of the page to see what the character might be, but when I right click on the page, I get this:

http://www.chrishajer.com/bbpress/copyright.png