Hofmockel.org

Installing an access control module removes the default "grant all" entry in node_access table. Uninstalling or disabling the module doesn't neccessary return the the default "grant all" privilege.

run the SQL code below to return the entry.

INSERT INTO node_access VALUES (0, 0, 'all', 1, 0, 0);

ref: http://drupal.org/node/12757#comment-42578