Quando faccio l'uppload della pagina xhtml ho il seguente errore:

Sorry, I am unable to validate this document because its content type is text/css, which is not currently supported by this service.

The Content-Type header is sent by your web server (or web browser if you use the file upload interface) and depends on its configuration. Commonly, web servers will have a mapping of filename extensions (such as ".html") to MIME Content-Type values (such as text/html).

That you received this message can mean that your server is not configured correctly, that your file does not have the correct filename extension, or that you are attempting to validate a file type that we do not support yet. In the latter case you should let us know that you need us to support that content type (please include all relevant details, including the URL to the standards document defining the content type) using the instructions on the Feedback Page.


Questa è la pagina web:

codice:
<?xml version="1.0" encoding="UTF-8"?> 
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
	<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
	<title>Web Utilities Kekko</title>
	
	Ho si usa il tag link per importare i css oppure import.
	<link rel="stylesheet" type="text/css" href="homePage.css" />

	<!--
	<style type="text/css">		

		@import url(homePage.css);	
							
		form {
			
			width: 20em;
			
		     }
		 
		fieldset{
		
			background-color: red;
				   
				  }	 
		 		
	</style>
		-->
</head>
<body>
	<div id="contenitoreGenerale">
		<div id="top">
			[img]webUtilities.gif[/img]
					
				<form id="utenteRegistrato" method="post" action="testdb.php">
					<fieldset >
						<legend>Accesso Utenti</legend>
							
						<label>Username:</label>
						<input type="text"></input>
						

								
						<label>Password:</label>
						<input type="password"></input>
						

								
						<button value="invia" type="submit">Invia </button>
						


					<label>Se non sei registrato clicca Qui</label>						
				</fieldset>				
			</form>						
		</div>
		<div id="barra">
			<table>
				<tr>
					<td>Registrazione </td>
					<td></td>					
					<td></td>
					<td></td>
				</tr>
			</table>
		</div>
	</div>
</body>
</html>
Perchè mi da errore per il css?