cron.php will not run in Wordpress, is_admin() call to undefined function

I have attempted to run the cron from a browser using these methods in Wordpress with 4.1.0

consolidated cron:
http://www.site.org/wp-content/plugins/civicrm/civicrm//bin/cron.php?name=do-not-delete&pass=xxx&key=xxx

specific job:
http://www.site.org/wp-content/plugins/civicrm/civicrm//bin/cron.php?job=process_mailing&name=do-not-delete&pass=xxx&key=xxx

Both result in this error:
Fatal error: Call to undefined function is_admin() in /home/capitol/www/www/wp-content/plugins/civicrm/civicrm/CRM/Utils/System/Base.php on line 49

The user "do-not-delete" is 'administrator' role