Error al validar

[serbc27]

AL validar la web a traves de W3c me da un error:

Line 235, Column 22: end tag for "tr" which is not finished
</tr><tr></tr><tr>

La linea del error es justo despues de:

echo '<tr>
<th>L</th><th>M</th><th>M</th><th>J</th><th>V</th><th>S</th><th>D</th>
</tr>';