There really isn't enough to go to give a decent answer.
- What is the provider system?
- How are you executing the consumer? Client? Server? XPages? Eclipse plugin?
- Is the provider/consumer in the same NSF?
I'd also recommend debugging using SOAPUI or similar tools.
The following wiki article explains how to do this:
http://www-10.lotus.com/ldd/ddwiki.nsf/dx/Testing_your_Domino_web_service_provider_and_consumer_using_SoapUI._