Mismatched Tag Error ......

I get this every once in a while.  It says "line 23, char 2, mismatched
tag".

This is the </head> tag.



***************************** 
This communication may contain information that is proprietary, privileged,
confidential or legally exempt from disclosure.  If you are not a named
addressee, you are notified that you are not authorized to read, print,
retain, copy or disseminate this communication without the consent of the
sender and that doing so may be unlawful. If you have received this
communication in error, please notify the sender via return e-mail and
delete it from your computer. Thank you. St. Jude Medical, Inc. 
*****************************