Yes, I see the errors on your product page. The table rows <tr> are started and closed </tr> but there is no columns <td></td> inside.
Take a look at the template that controls this page.customer/main/product_details.tpl
I see in the original templates you may have removed the sku number from the page:
Code:
<tr>
<td class="property-name property-name2">{$lng.lbl_sku}</td>
<td class="property-value" id="product_code" colspan="2">{$product.productcode|escape}</td>
</tr>
You need to also remove the <tr></tr> tags.