Warning message at top of 'pending posts' page

Hi

I am getting the following error message at the top of the page when I go to the pending posts section of my site - any idea why this has been coming up?

Warning
JUser: :_load: Unable to load user with ID: 233

JFile: :read: Unable to open file: /home/blatantl/public_html/components/com_k2/js/k2.js?v2.6.8&sitepath=/

JFile: :read: Unable to open file: /home/blatantl/public_html/ajax.googleapis.com/ajax/libs/jquery/1.8.2/jquery.min.js


thanks