I find it quite remarkable that out of 6 answers, none of them have mentioned the real source of the problem.
Collapsing margins on the last p inside #fw-footer is where that extra space is originating from.
A sensible fix would be to add overflow: hidden to #fw-footer (or simply add margin: 0 on the last p).
You could also just move the script inside that last p outside of the p, and then remove the p entirely; there’s no need to wrap a script in a p. The first p (#fw-foottext) has margin: 0 applied, so the problem won’t happen with that one.
As an aside, you’ve broken the fix I gave you in this question:
CSS3 gradient background with unwanted white space at bottom
You need html { height: 100% } and body { min-height: 100% }.
At the moment, you have html { height: auto } being applied, which does not work:
(This happens with a window taller than the content on the page)