ASYNC_NETWORK_IO wait issue with DTS

Hi,

I'm having a problem with DTS and wait types that seems to be baffling me at the moment.

I am using DTS on a SQL Server 2005 database (yes I know but thats the only option I have atm). Everytime I run the transform task to bulk insert the results of this query into another table the INSERT is blocked with the wait type of ASYNC_NETWORK_IO.

SELECT    bhp.P_URN,
          NULL AS OrgID,
          NULL AS LocID,
          ra.LocID As SuppliedLocID,
          t.BinTerritoryID,
          dbo.fn_dGetStandardDate(ra.DATE) AS ActivityDate,
          CASE CALL_TYPE
             WHEN 'Something' THEN 'MT'
             ELSE 'CA'
          END AS ActivityTypeID,
          NULL AS CustType,
          ra.ClientActivityID
FROM      nov_RAWActivity ra
             INNER JOIN
          History_Mirror.dbo.People bhp
             ON CAST(RIGHT(ra.URN, LEN(ra.URN) -1) AS int) = bhp.P_URN
             INNER JOIN
          Core.dbo.Territory t
             ON ra.TERRITORY = t.ClientTerritoryID
             LEFT OUTER JOIN
          Staging.dbo.xxx_Activity sa
             ON ra.ClientActivityID = sa.ClientActivityID
WHERE     ISNUMERIC(RIGHT(ra.URN, LEN(ra.URN) -1)) = 1
AND       t.CompanyID = 'xxx'
AND       sa.ClientActivityID IS NULL

As you can see from the query there are some hideous things i have to do to the data in joins because it is a data warehouse taking raw data from a client and formatting it into the format of the warehouse, but this, run as a simple SELECT on its own takes about 20 seconds to return 400,000 rows so the query should be fine (although not pretty).