You need to look into semantic coding. You're not closing your img tags properly, and you should be using the <p> tag rather than <span> to wrap your paragraph, as that's what it is. This is the reason your text isn't applying to the margins you've set.
Also you can simplify your margin settings in one simple line... for example:
border-right: #CBCBCB 1px solid;
border-left: #CBCBCB 1px solid;
does exactly the same as your four lines. The numbers respectively apply to the top, right, bottom then left margins.
margin: 100px 200px 50px 200px;
EDIT: You don't even have a doctype declaration! I suggest you look up using doctypes so that your page does not render in quirks mode in IE and you will find it easier to code cross browser!