If you run boilerplate code through HTML validator, it gets tripped up on this line:
<HTML xmlns="http://www.w3.org/1999/xhtml">
Exact error thrown is "there is no attribute "xmlns"" with description of:
You have used the attribute named above in your document, but the document type you are using does not support that attribute for this element. This error is often caused by incorrect use of the "Strict" document type with a document that uses frames (e.g. you must use the "Transitional" document type to get the "target" attribute), or by using vendor proprietary extensions such as "marginheight" (this is usually fixed by using CSS to achieve the desired effect instead).
As long as you keep the doctype above the tag intact there should be no problems. Validates for me at least on validator.w3.org (the 3 errors the boilerplate throws is in regards to tables and target attribute).
If you run boilerplate code through HTML validator, it gets tripped up on this line:
Exact error thrown is "there is no attribute "xmlns"" with description of: