Problem with Web Service Parameter

Question

I am having a problem with a simple web service that accepts a parameter. For example: [WebMethod] public string HelloWorld(string strParam) { return "Hi"; } This method returns a 500 Internal Server Error. When I remove the parameter: [WebMethod] public string HelloWorld() { return "Hi"; } the web service works fine. Does anyone have any experience with this or know of a direction to log what is causing the error (nothing is in the event log). Thanks.