Dear Sheraz,
perhaps you can create the stream arc first, and then save the feature arc as a shape file. to create the stream arc, we can use DEM module, create some outlet points, and convert DEM to stream arc.
otherwise, you can also create the basin and save the result (feature arc in shapefile).
i hope that helps
any comment?
*i'm not the specialist, i'm just a user, trying to get along with this software more and more, so let's share*