How to remove Error "Unable to connect: Invalid URI:" ?

Hi friends,

I've created a simple chating application using Silverlight 4 having clint-server model. In this user first enter its name in the textbox and click the button in order to enter in the chat. It was running good but suddenly I'm stuck with the error. When I enter the name in the textbox and click the button I'm getting this error.

"Unable to connect: Invalid URI: The hostname could not be parsed.. Continuing with out connecting to server!!" or "The silverlight project you are about to debug uses web service. Calls to the web service will fail unless the silverlight project is hosted in and launched from the same web project that contains the web services"

Please help me guys..