End tag for element ... which is not open
Cause:
The validator found an end tag for the above element, but that element is
not currently open. This is often caused by:
- a leftover end tag from an element that was removed during editing,
- or by an implicitly closed element. If you have an error related to an element being used where it is not allowed, this error will disappear as soon as you fix the original problem.
If this error occured in a script section of your document, you should probably
read this FAQ entry.
Example:
 | <b>abc</b></b> |
 | <b>abc</b> |
Solution:
For a closing tag, remove the closing tag or add the missing opening tag before.
References: