I'm using JBoss 4.0.1 with JWSDP 1.5, you are missing the jaxrpc-impl.jar which you should find in $JWSDP_HOME//jaxrpc/lib/jaxrpc-impl.jar
I copied this into my $JBOSS_HOME/client directory.
You have two choices:
1) Use the web service client implementation we provide. In that case, you don't need BasicService and StubBase.
See the wiki on the client programming model or Consuming a WS Step by Step
2) Use any other WS client like JWSDP - it is not WS4EE compliant. In that case use their jars. It should not leek into $JBOSS_HOME/client.