The errors you mention are HTML issues, not CSS. Most of them seem to be related to the order of tags. Your best bet would probably be to get Firefox and the HTML Validator Addon, which will allow you to view the page source code with the errors highlighted. But as a basic overview:
1. This error is caused by <input> being in the wrong place. An <input> tag must be inside a block level container, be it a text tage (p, h1, div, etc) in order to be considered valid. Another possibility is that the <input> tag is inside an inline tag such as <a> or <span>.
2. Same as 1.
3. The <table> is empty. A <table> must contain at least one row, and that row must contain one cell for the document to validate.
4. You have an extra </div> tag. Elsewhere in the document, you already closed the <div>.
Unfortunately I can't be much more helpful because when I ran my checker on the page it found several more items.