Scrollbar not appearing

I assume you mean that your content section is not scrolling? That’s because you have the content div inside the line2 div — which is set to fixed position:

<div id="line2">
<div id="line3"> </div>
<div id="content">
<div id="footer"> </div>

You also have a lot of mark-up errors on the page — so you would be well advised to deal with those. I’d suggest validating the CSS as well.

http://codex.ww.wp.xz.cn/Validating_a_Website