SQL Activity manager- I have a process that is running 2 transaction and is being blocked by another process at awaiting command

/****** Object:  Trigger [scheme].[mihaddcost_ins]    Script Date: 06/17/2008 22:25:58 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER TRIGGER [scheme].[mihaddcost_ins]
 
ON [scheme].[opdetm]
 
AFTER INSERT
 
AS
 
--Trigger used to modify the driver field in opdetm with costs stored in stockm.
 
--The value entered depends on the currency of the customer.
 
--stockm.setup cost holds the sterling value
 
--stockm.shelf_life holds the euro value
 
 
 
    INSERT INTO [scheme].[opdetm_cost]
        
    SELECT i.order_no
          , i.order_line_no 
          , CASE WHEN RTRIM(LTRIM(c.currency)) = 'EUR' AND  s.shelf_life > 0
                              THEN s.shelf_life 
                              WHEN RTRIM(LTRIM(c.currency)) = 'EUR' AND  s.shelf_life = 0
                              THEN s.standard_cost
                              WHEN RTRIM(LTRIM(c.currency)) = '' AND s.setup_cost =0
                              THEN s.standard_cost
                              WHEN RTRIM(LTRIM(c.currency)) = '' AND s.setup_cost > 0
                              THEN s.setup_cost
                              ELSE 0
                          END
           * CASE WHEN i.order_line_status ='B'
							  THEN i.order_qty
							  WHEN i.allocated_qty>0
							  THEN i.allocated_qty
							  WHEN i.despatched_qty>0
							  THEN i.despatched_qty
							  ELSE i.order_qty
						  END
 
          , CASE RTRIM(LTRIM(c.currency)) 
                      WHEN 'EUR' THEN i.val/1.27
                      ELSE i.val END AS STGVAL
          , o.date_entered
          , i.line_type  
          , o.territory 
       FROM INSERTED i
       JOIN [scheme].[opheadm] o
         ON o.order_no = i.order_no
       JOIN [scheme].[slcustm] c
         ON c.customer = o.customer
       LEFT JOIN [scheme].[stockm] s
         ON s.[product] = i.product 
        AND s.[warehouse]= i.warehouse