hi George
you need define a workflow to automatically monitor this. when IDOC error issues, the event of BOR will trigger this workflow, then send a email to users.
you can googling 'Configure workflow notifications for IDocs in error status', there are some detail steps in SAPTechnical.
if you want more theory, refer this like, http://help.sap.com/saphelp_nw04/helpdata/en/b9/c086d4965611d2a5ca0060087832f8/frameset.htm -----> Error Handing
regards,
Archer