Workflow Mailer Log / Errors

I am seeing entries in our workflow mailer log that include entries such as "Not sending notification {1150114}because the notification mail status is null OR not 'MAIL'"  When I query for that notification ID in the wf_notifications table I find one record.  The Subject for the notification is "Error in Workflow APEXP/1699412 [WF_ERROR] ERROR_MESSAGE=3835: Error '-20002 - ORA-20002: [WFMLR_DOCUMENT_ERROR]' encountered during execution of Generate function 'WF_XML.Generate' for event 'oracle.apps.wf.notification.send'. ERROR_STACK=" 

This resulted in a pair of notifications showing up in the Administrator Workflow notifications list. 

I checked the user who submitted the expense report and saw their mail preference was MAILHTML in the WF_LOCAL_ROLES table.  I also checked to be sure that the language being used in EBS was the same one for WF.  It was.