Editor and page don't match

Hello,

My question is very simple. 🙂

This is the code: http://oi60.tinypic.com/5cd9o4.jpg
This is how it looks in the visual editor: http://oi58.tinypic.com/afamig.jpg
This is how it looks when I load the page in Firefox: http://oi62.tinypic.com/9tldgn.jpg

They don’t match, so I’m doing something wrong. Could someone help me on this?

Thanks in advance! 🙂