[Plugin: User Access Manager] WordPress database error : duplicate entry

Hi,

I’ve recently started getting the following error (number of duplicate entry errors changes from time to time) when I try to update any kind of post restricted to a user group.

WordPress database error: [Duplicate entry '305-attachment-1' for key 'PRIMARY']
INSERT INTO wp_uam_accessgroup_to_object ( group_id, object_id, object_type ) VALUES ( '1', '305', 'attachment' )

WordPress database error: [Duplicate entry '305-attachment-1' for key 'PRIMARY']
INSERT INTO wp_uam_accessgroup_to_object ( group_id, object_id, object_type ) VALUES ( '1', '305', 'attachment' )

WordPress database error: [Duplicate entry '305-attachment-1' for key 'PRIMARY']
INSERT INTO wp_uam_accessgroup_to_object ( group_id, object_id, object_type ) VALUES ( '1', '305', 'attachment' )

WordPress database error: [Duplicate entry '305-attachment-1' for key 'PRIMARY']
INSERT INTO wp_uam_accessgroup_to_object ( group_id, object_id, object_type ) VALUES ( '1', '305', 'attachment' )

My steps to get this error are this exactly: In the admin panel, select a page and click “edit”. Then on the edit page, press “update”. Then I get a blank page with the errors above.

Any ideas?

Thanks.

http://wordpress.org/extend/plugins/user-access-manager/