Error calling API inv_move_order_pub.process_move_order

I'm trying to create a move order by calling the API inv_move_order_pub.process_move_order.  I'm using EBS 12.1.3 on Solaris.

The code below always returns status E, with the message 'Header status is not valid'

I've tried changing the header status, order and transaction types, but continue get the same error....

Can anyone help?

DECLARE
   PROCEDURE create_move_order
   IS
      l_hdr_rec         inv_move_order_pub.trohdr_rec_type              := inv_move_order_pub.g_miss_trohdr_rec;
      l_line_tbl        inv_move_order_pub.trolin_tbl_type              := inv_move_order_pub.g_miss_trolin_tbl;
      x_return_status   VARCHAR2 (1);