WYSIWYG module errors

I receive the following error when attempting to edit a page. I have installed ckeditor - but maybe in the wrong place? New to Drupal and not sure where to start to resolve this problem.

warning: include_once(./sites/all/modules/wysiwyg/editors/ckeditor.inc) [function.include-once]: failed to open stream: Permission denied in /var/www/html/drupal/sites/all/modules/wysiwyg/wysiwyg.module on line 791.
warning: include_once() [function.include]: Failed opening './sites/all/modules/wysiwyg/editors/ckeditor.inc' for inclusion (include_path='.:/usr/share/pear:/usr/share/php') in /var/www/html/drupal/sites/all/modules/wysiwyg/wysiwyg.module on line 791.