Description
   The array format must be:  
    array(error code => 'message template',...)
  
   Error message parameters passed into 
   
    push()
   
   will be used as input  for the error message.  
   
   If the template is 'message %foo% was %bar%', 
   and the parameters are 
   array('foo' => 'one', 
   'bar' => 'six'), 
   the error message returned will  be 
   'message one was six'