You have three <p> tags that are opened but not closed, and that is giving a whopping 97 errors. Close those paragraphs and you should find they go away!
Mianly due to the Implicit </p> delete it see: <!-- Content –></p> you also have a few empty DIV and SPAN elements. But remove that implicit P and it will get far easier to workout the other errors.
Often a single coding error, such as an unclosed <p> tag, will generate a plethora of validation errors; one real error causes a cascade effect. When you get the “yikes, you have 3,459 errors!” warning, you usually don’t have nearly that many.
It sounds like you could benefit from using a ‘HTML Lint’ in conjunction with the validator since the Lint might catch some more faults for you. Have you installed: http://users.skynet.be/mgueury/mozilla/