for starters all your asp should be inside a content place holder. There should not be any Head sections for instance.
Tim

>Hi
>
>I'm trying to retrofit fit some pages with a master page.
>
>On the design view there is an error displayed
>
>The page contains markup that is not valid when attached to a master page.
>
>Correct the problem in Code view
>
>But nothing seems to be highlighted in the code view.
>
>Any ideas what I should be looking for ?
>
>Update
>
>Its ok I didn't have contentplaceholder