THere's nothing wrong with your LINK element. The rest of your HTML is a problem however.
Get the HTML right; use The Validator. Make certain that the page and the style sheet are in the same directory. And make sure that you have no STYLE tags in the style sheet.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<meta name="Content-Style-Type" content="text/css">
<link rel="stylesheet" type="text/css" href="p4mestylesheet.css">
If all the above fail then post your URL.
“The power of the Web is in its universality. Access by everyone regardless of disability is an essential aspect.”
—Tim Berners-Lee, W3C Director and inventor of the World Wide Web