jdeveloper webservices setings

[wedany]

i am trying to make a webservice to try it with jdeveloper over oc4j
and as u know there is a test way provided by jdeveloepr to test ur webservice after publishing it
after i compliled the calsses and deploy it and open the url http://localhost:8888/jdeveloper_apl...ebservice_name
and evry thing is ok till now and the page apear carying the method services name and when i click the method servic ename evry thing is still ok and the form apear requesting the input of the method if any with an invoke button or with the invoke button alone if no input was required and 2 link below the Proxy Jar and the Proxy Source so till now evry thing is ok

but after i press the invoke button or when i press the link proxyjar or Proxy Source the explorer show the usual error page HTTP 500 - Internal server error Internet Explorer so nothing work till the end

does any one expert in webservices with jedeveloepr know what do i miss to set so that the trial work?