C# – Consume web service from Class Library

I have successfully created an ASP.net website to make calls to a Soap Web service.

Now I need to turn it into a Class Library that I can call via Com from Classic ASP.

This post on Consume web service in asp.net app from a class library says that I need to add the web service as use "Add Service Reference" instead of "Add Web Reference" to add a reference to the Webservice.

When I try to do that I get an error:

Metadata contains a reference that
cannot be resolved:
'http://theURL.com:8008/asmx/publicServiceAddress.asmx?wsdl'.
There was an error downloading
'http://theURL.com:8008/asmx/publicServiceAddress.asmx?wsdl'.
Unable to connect to the remote server
A connection attempt failed because
the connected party did not properly
respond after a period of time, or
established connection failed because
connected host has failed to respond
77.95.80.35:8008 Metadata contains a reference that cannot be resolved:
'http://theURL.com/asmx/publicServiceAddress.asmx'.
Metadata contains a reference that
cannot be resolved:
'http://theURL.com/asmx/publicServiceAddress.asmx'.
If the service is defined in the
current solution, try building the
solution and adding the service
reference again.

…but when I click on advanced and then add then "Add Web Reference" I can add it fine.

Questions:

1) Is it necessary to use "Add Service Reference" instead of "Add Web Reference"?
2) Why, what's the difference?
3) What are potential causes of this error, and how can I figure this out, for instance I don't know why it's going to port 8080 to look for the WSDL http://theURL.com:8008/asmx/reguspublic.asmx?wsdl when it should go to http://theURL.com/asmx/reguspublic.asmx?wsdl