Portfolio page - personally I would'nt worry about the 'width' being obsolete. That's just complete bollocks on the part of the WC3. Got to take what they say with a pinch of salt and move on.

If you did want your page to validate further then you would have to give the table an 'id' (I've given it the 'id' of gallery (see below)). Also you would need to use some inline css styling to set one <td> to have the text aligned in the center of the cell and another <td> to align the text to the right (see inline styling below). Also you dont need the <div> tags that are wrapped around your <p> tags so I have removed them. Honestly though nothing in your current page is going to affect its performance. The 'lightbox' attribute on the <a> tag needs to be there for the lightbox to work, its just a WC3 failure to acknowledge anything else, other than what they say, as being accepatable. I don't treat validation that seriously, just write clean code and youre good to go!

<div class="content">

    <table id="gallery">

      <tr>

        <td><h1>Gallery</h1></td>

        <td style="text-align: center;">

          <p class="content">click on image to see the full size photo</p>

        </td>

        <td style="text-align: right;">

          <h3><a href="portfolio2.html">Next <span class="line">&gt;&gt;</span></a></h3></td>

      </tr>

    </table>

Then add the below css to your stylesheet:

#gallery {

    width: 1260px;

}

#gallery td {

    width: 420px;

}

For the first two pages, what you are getting is not errors - they are warnings that notify you that you have used obsolete markup in those tables.  The pages will be rendered properly, at least in the current set of browsers and probably beyond that.  There will be small risk in just leaving it.  Me?  I would change it for my pages, but that's because I like to have valid markup to the extent that I can make it be so.

As for the tabbing and alignment issue, can you explain more about what is troubling you there?

Finally, I think 1260px is too wide (by ~300px) for a general public site.

The easy way to fix your header would be to split the image into two small pieces, make the right image be the background image of the container, and use the background-position style to move it to the right:

background-position:right top;

<div style="width:1200px;overflow:hidden;"><img width="250" style="float:right;"><img width="185" style="float:left;"></div>

It's as simple as that.

Change this -

<ol>

      <ol>

        <li>Pre Wedding shoot with your choice of 5 prints up to 12&rdquo; x 8&rdquo;</li>

        <li>Whole day of photography – Including a 2nd Photographer/Assistant</li>

        <li>Your choice of wedding album from our collection with 15 double-sided pages (30 pages) for your selected photos</li>

        <li>24&rdquo; x 24&rdquo; framed print or canvas</li>

        <li>Two high quality albums and 10&rdquo; x 10&rdquo; framed prints for parent&rsquo;s gifts</li>

        <li>A DVD with all the photos from the day suitable for printing</li>

        <li>Personalised slideshow of your pictures set to music</li>

        <li>Access to your photos on our online gallery to share with your friends and family</li>

      </ol>

    </ol>

to this -

<ol>

   <li>Pre Wedding shoot with your choice of 5 prints up to 12&rdquo; x 8&rdquo;</li>

        <li>Whole day of photography – Including a 2nd Photographer/Assistant</li>

        <li>Your choice of wedding album from our collection with 15 double-sided pages (30 pages) for your selected photos</li>

        <li>24&rdquo; x 24&rdquo; framed print or canvas</li>

        <li>Two high quality albums and 10&rdquo; x 10&rdquo; framed prints for parent&rsquo;s gifts</li>

        <li>A DVD with all the photos from the day suitable for printing</li>

        <li>Personalised slideshow of your pictures set to music</li>

        <li>Access to your photos on our online gallery to share with your friends and family</li>

</ol>

And your 'tabbing' error will go away.  It is not proper syntax to have <ol><ol>.  The only tag that can follow <ol> is <li>.  When you are struggling with these messages, take a look at the code and read the message in the context of the code you see at that line #.  You'll figure it out.

Add some left margin (inline example shown below) but preferably do it in your css stylesheet

<ol style="margin-left: 30px;">

css stylesheet example:

ol {

margin-left: 30px;

}