How to install a Web Service?

Questions
1

Dear members,
I am very new at using web services. I have started with the examples in the documentation.

<< WebServices`

and then

InstallService["http://localhost:8080/webMathematica/Examples/\
WebServices/Hello.m?wsdl"]

I got the following error

InstallService::endpoint: Invalid SOAP endpoint: http://localhost:8080/webMathematica/Examples/WebServices/Plot.m?wsdl

I will appreciate your help in this seemingly easy matter.

Regards
Jesus