We are using SOAP to call a web service. Our product has been deployed to many sites, and is working fine at all but one. At that site, on at least two PCs, the code throws an exception, with the above error message. My research indicates that the action parameter is optional, and there is no mention of it in our wsdl definition of our web service.
Because this only appears to be an issue on PCs at this site, it looks like it's something to do with the setup of their PCs. They are running Win2K, and windows update shows that they're relatively up to date. Maybe they're missing something that is needed by SOAP, or they have sonething installed that interferes with it?
I don't think it's a firewall issue, because IE can access the URL of the web service.
Does anyone have any ideas?