Re: <td background="images/bg.jpg">

Ok then, all sorted
*_Solutions_*
removed the border and target attributes from index.shtml page now validated
 
*_CSS_*
Replaced it in the folder Docs and changed the url to this
body
{
background-image:url('../Pics/Background6.jpg')
}

*In html documents changed this*
 <link rel="stylesheet" type="text/css" href="Docs/MasterStyle.css">
  <base target="_self">
</head>

*_to this_*
  <base target="_self">
 <link rel="stylesheet" type="text/css" href="../Docs/MasterStyle.css">
</head>

seems like those two preceding dots and forward slash are needed.
Thanks to all those who have pointed me in the right direction.

One thing though, if border="0"  in frames and this works across all 
browsers, then why not let it be validated?