[VE][2316] Error Message Feedback

Validating http://www.catchingperverts.co.uk/ 
Error [2316]: "" 

Any help at all please! I thought the site was ok, until I did this test:-(

It is a very important site, and I would love your help please!
 
  Follow the instructions at 
http://validator.w3.org/feedback.html#errormsg ]