Error in validator

In the validator, when a page is Valid XHTML 1.1, there are an error:

line 54 column 3 - Warning: <table> lacks "summary" attribute

<form id="form" method="get" action="check">
  <table class="header">
    <tr>
    <th>Result:</th>
    
    <td colspan="2" class="valid">
      
        Passed validation
      
    
    </td>

    </tr>
    <tr>

      <th>File:</th><td colspan="2">upload://Form Submission</td>

    </tr>

    <tr><th>Modified:</th><td colspan="2"></td></tr>
    <tr><th>Server:</th><td colspan="2"></td></tr>

    <tr><th>Size:</th><td colspan="2"></td></tr>
    <tr><th>Content-Type:</th><td colspan="2"></td></tr>


Bye, Lito.