Problem with Webservice using vb.net

I have a (Subprogram) Webservice that I am trying to run from vb.net

I have used the same code successfully with an Object Webservice.

I am getting the following error when executing:

resultXML = webService.run(callContext, "WSMANTIMP", readXMLEach(appPath & "\importSOH.xml"))

An error occurred when loading the Web service description [WSMANTIMP] (see file WEBS)

WSMANTIMP is the Webservice Publication name and it test successfully when tested in: 

All>Administration>Administration>Web Services > SOAP Generic Web Services
I hope someone has an answer to this problem.
Thanks,
Mario