After Html Validation, I had many errors that I was able to resolve, however, the following 4 errors, I can't resolve. This is from the w3.org site validator.

The page in question: http://www.reunitemysite.com/main.html

Error Line 264, Column 39: there is no attribute "ONLOAD"

<iframe id="glu" name="iframe" onload="resize_iframe()" style=" border: 0px sol…

✉

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).

This error may also result if the element itself is not supported in the document type you are using, as an undefined element will have no supported attributes; in this case, see the element-undefined error message for further information.

How to fix: check the spelling and case of the element and attribute, (Remember XHTML is all lower-case) and/or check that they are both allowed in the chosen document type, and/or use CSS instead of this attribute. If you received this error when using the <embed> element to incorporate flash media in a Web page, see the FAQ item on valid flash.

Error Line 266, Column 5: end tag for "IFRAME" omitted, but its declaration does not permit this

</td>

✉

You forgot to close a tag, or
you used something inside this tag that was not allowed, and the validator is complaining that the tag should be closed before such content can be allowed.

The next message, "start tag was here" points to the particular instance of the tag in question); the positional indicator points to where the validator expected you to close the tag.
Info Line 264, Column 1: start tag was here

<iframe id="glu" name="iframe" onload="resize_iframe()" style=" border: 0px sol…

Error Line 269, Column 9: end tag for element "IFRAME" which is not open

</iframe>

✉

The Validator found an end tag for the above element, but that element is not currently open. This is often caused by a leftover end tag from an element that was removed during editing, or by an implicitly closed element (if you have an error related to an element being used where it is not allowed, this is almost certainly the case). In the latter case this error will disappear as soon as you fix the original problem.

If this error occurred in a script section of your document, you should probably read this FAQ entry.
Error Line 270, Column 7: end tag for "DIV" omitted, but its declaration does not permit this

</body>

✉
You forgot to close a tag, or
you used something inside this tag that was not allowed, and the validator is complaining that the tag should be closed before such content can be allowed.

The next message, "start tag was here" points to the particular instance of the tag in question); the positional indicator points to where the validator expected you to close the tag.

Info Line 129, Column 1: start tag was here

<div style="vertical-align: top;" class="gradient">

why are you using an iframe to load your content into? why not use normal pages - you do realiset that using iframeds means that users can't book mark individual pages?

it would also,incidentally clear most/all of those errors.

you also have visual/layout errors in your design too if you would like some help with those give us a shout

and this is - even if it's true - is not acceptable any more
"This website is Best Viewed at 1024 x 768 Resolution with Mozilla Firefox or Google Chrome Web Browsers!"

There is NO onload attribute for the iframe element and that "error" breaks the opening tag for the parser.

The validator is a fairly simple beastie and easily confused, so one error can cascade into hundreds of warnings.