#1 Remove height values from divisions. Page height is determined by content, not explicit values.
font-family: Verdana, Geneva, sans-serif;
#2 Same as #1 above. Height is limiting how much content will fit inside your #main div.
The colors are pretty dark. Where are you seeing this gap?
As far as other code errors go:
- Line 42 - Change style="font-size:14px":"color:#FFF" to style="font-size:14px;color:#FFFFFF;"
- Line 54, 56, 91, 92 - the blockquote. Do you understand what a blockquote is? If so, you do you realize you have 2 nested blockquotes surrounding your entire body? Why do you need them? I recommend deletion
The <blockquote> tag is intended to delimit a bit of quoted text on your page. It happens to also indent the text, and as a result is commonly used erroneously as a general indentation tool. That's an improper use. While it won't cause your page to fail validation, it will confuse any semantic evaluation of the 'meaning' of the code.
Ok, I see it is now that the blockquote is gone. That's because the floated element is taken out of the flow of the document and is longer than the container that it's in. So the background is not streteching. You can add some more content or just add padding to the bottom of your main container to try and add more background there. Not ideal, but that's the simplest way I see to fix the issue.