hello

I created a new view that has custom content type.

when no user is logged in and when i access this page i get:
user warning: Unknown column 'node_data_field_due_date.field_due_date_value' in 'where clause' query: SELECT DISTINCT node.nid AS nid, node.type AS node_type FROM node node INNER JOIN node_access na ON na.nid = node.nid WHERE (na.grant_view >= 1 AND ((na.gid = 0 AND na.realm = 'all') OR (na.gid = 0 AND na.realm = 'og_public'))) AND ( (node.type in ('homework')) AND ((DATE_FORMAT(node_data_field_due_date.field_due_date_value, '%Y-%m') <= '2011-12' AND DATE_FORMAT(node_data_field_due_date.field_due_date_value2, '%Y-%m') >= '2011-12')) ) in C:\xampp\htdocs\drupal-6.22\sites\all\modules\views-6.x-2.12\views\includes\view.inc on line 775.

at the top of the calendar page.

This error does not occur when a user is logged in.

moreover, I receive from time to time, upon saving the view, an ajax error appearing as a pop-up message saying:
an error occurred at /admin/build/views/ajax/preview/mycalendar

Error description: 404: Not found

Any idea please?
thank you