Error Serialization/Deserialization failed Consume Web Service:

Hello Everybody,

I have a problem when Consume Web Service. In the Request I send a string and I expected Response value "HOLA MUNDO" , but I find a problem in the comunication and return me a message "Serialization/Deserialization failed"

     http://screencast.com/t/Dork5yFA

     could anyone help me ?

     Thanks you.

     Luis Minaya