Delegated Webservice Problem

I set up a webservice controller like this:

class ServiceController < ApplicationController
wsdl_service_name ‘Service’
wsdl_namespace ‘urn:inuservicexml’

web_service_dispatching_mode :delegated
web_service_scaffold :invoke

web_service :userinfo, UserService.new
end

In the UserService class and UserApi class, I defined a login method,
so I tried to access the login service by this url,
“localhost:3000/service/userinfo/login”. But this generated me a very
weird warning page –


Internal protocol error: undefined local variable or method source' for REXML::SourceFactory:Class Backtrace: c:/ruby/lib/ruby/1.8/rexml/source.rb:20:increate_from’
c:/ruby/lib/ruby/1.8/rexml/parsers/baseparser.rb:123:in stream=' c:/ruby/lib/ruby/1.8/rexml/parsers/baseparser.rb:100:ininitialize’
c:/ruby/lib/ruby/1.8/rexml/parsers/streamparser.rb:6:in initialize' c:/ruby/lib/ruby/1.8/rexml/document.rb:185:inparse_stream’
c:/ruby/lib/ruby/1.8/xmlrpc/parser.rb:717:in parse' c:/ruby/lib/ruby/1.8/xmlrpc/parser.rb:475:inparseMethodCall’
c:/ruby/lib/ruby/1.8/xmlrpc/marshal.rb:63:in load_call' c:/ruby/lib/ruby/1.8/xmlrpc/marshal.rb:32:inload_call’


And when I run funcational tests associating with this webservice, it
told me “ActionWebService::Container::Delegated::ContainerError: no
such web service ‘login’”.
I really have no idea what’s going on. I have been stucking on this
problem for days… Please help me on this…
Thank you very much~