Create DTS package

The following code works with VB 6.0, but it does not work with VB 2005.
 Dim oTask As DTS.Task
 Dim oCustomTask1 As DTS.DataPumpTask2
oTask = CType(goPackage, DTS.Package).Tasks.New("DTSExecuteSQLTask")
oTask.Name="ssss"
oCustomTask1 =oTask.CusomTask

the error is "Unable to cast COM object of type 'System.__ComObject' to interface type 'DTS.DataPumpTask2'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{1002090A-EB1C-11CF-AE6E-00AA004A34D5}' failed due to the following error: No such interface supported (Exception from HRESULT: 0x80004002 (E_NOINTERFACE)).".

The server is the microsoft sql server 2005 with sp4.

Please help.