Thanks for that - when I get up to speed I will treat newbies as well as you have treated me. The link you gave me tells me to add the following files to my JBOSS_HOME/lib directory. jboss-jaxrpc.jar jboss-saaj.jar jaxb-api.jar jaxws-api.jar I did that, but unfortunately I got the same error. I then decided to revert to JDK5 and the whole thing worked fine last night (was using demo code that I downloaded from a website) Came into work early this morning, really happy that I was going get round to writing the address lookup web service that was due in last Friday. But I am getting a bunch of errors again. I think it is because the return type on my web service is a complex type;- Exception in thread "main" org.jboss.ws.WSException: Cannot obtain java type mapping for: {http://session.address.cmmgroup.com/}getAddressByPostCode at org.jboss.ws.metadata.builder.jaxrpc.JAXRPCMetaDataBuilder.processDocElement(JAXRPCMetaDataBuilder.java:627) at org.jboss.ws.metadata.builder.jaxrpc.JAXRPCMetaDataBuilder.buildParameterMetaDataDoc(JAXRPCMetaDataBuilder.java:886) at org.jboss.ws.metadata.builder.jaxrpc.JAXRPCMetaDataBuilder.setupOperationsFromWSDL(JAXRPCMetaDataBuilder.java:214) at org.jboss.ws.metadata.builder.jaxrpc.JAXRPCClientMetaDataBuilder.buildMetaDataInternal(JAXRPCClientMetaDataBuilder.java:217) at org.jboss.ws.metadata.builder.jaxrpc.JAXRPCClientMetaDataBuilder.buildMetaData(JAXRPCClientMetaDataBuilder.java:134) at org.jboss.ws.metadata.builder.jaxrpc.JAXRPCClientMetaDataBuilder.buildMetaData(JAXRPCClientMetaDataBuilder.java:86) at org.jboss.ws.core.jaxrpc.client.ServiceImpl.(ServiceImpl.java:111) at org.jboss.ws.core.jaxrpc.client.ServiceFactoryImpl.createService(ServiceFactoryImpl.java:157) at org.jboss.ws.core.jaxrpc.client.ServiceFactoryImpl.createService(ServiceFactoryImpl.java:128) at com.cmmgroup.address.client.RunAddressAsWebService.main(RunAddressAsWebService.java:27) I'm not clear from the other forums if there is a resolution to this as I am already using the latest version of JBossWs. My mood has changed from one of despair to hysteria....I am both laughing and crying at regular intervals. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4066915#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...