an error with my wordpress

Warning: require_once(Text/Diff/Renderer.php) [function.require-once]: failed to open stream: No such file or directory in /home/cantbid1/public_html/blog/wp-includes/Text/Diff/Renderer/inline.php on line 17

Fatal error: require_once() [function.require]: Failed opening required ‘Text/Diff/Renderer.php’ (include_path=’.:/usr/lib/php:/usr/local/lib/php’) in /home/cantbid1/public_html/blog/wp-includes/Text/Diff/Renderer/inline.php on line 17