Example 'hello word' produce error (see below). Help me please!!!

Thanks in advance,

Primoz

error description
Object reference not set to an instance of an object.
Description: An unhandled exception occurred during the execution of the
current web request. Please review the stack trace for more information
about the error and where it originated in the code.

Exception Details: System.NullReferenceException: Object reference not set
to an instance of an object.

Source Error:

Line 1201:
Line 1202:    OperationBinding FindHttpBinding(string verb) {
Line 1203:        foreach (ServiceDescription description in
serviceDescriptions) {
Line 1204:            foreach (Binding binding in description.Bindings) {
Line 1205:                HttpBinding httpBinding =
(HttpBinding)binding.Extensions.Find(typeof(HttpBinding));

Source File:
d:\winnt\microsoft.net\framework\v1.1.4322\Config\DefaultWsdlHelpGenerator.a
spx    Line: 1203

Stack Trace:

[NullReferenceException: Object reference not set to an instance of an
object.]
  ASP.DefaultWsdlHelpGenerator_aspx.FindHttpBinding(String verb) in
d:\winnt\microsoft.net\framework\v1.1.4322\Config\DefaultWsdlHelpGenerator.a
spx:1203
  ASP.DefaultWsdlHelpGenerator_aspx.get_HttpPostOperationBinding() in
d:\winnt\microsoft.net\framework\v1.1.4322\Config\DefaultWsdlHelpGenerator.a
spx:441
  ASP.DefaultWsdlHelpGenerator_aspx.get_ShowingHttpPost() in
d:\winnt\microsoft.net\framework\v1.1.4322\Config\DefaultWsdlHelpGenerator.a
spx:456
  ASP.DefaultWsdlHelpGenerator_aspx.__Render__control13(HtmlTextWriter
__output, Control parameterContainer) in
d:\winnt\microsoft.net\framework\v1.1.4322\Config\DefaultWsdlHelpGenerator.a
spx:1435
  System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) +27
  System.Web.UI.HtmlControls.HtmlContainerControl.Render(HtmlTextWriter
writer) +29
  System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +243
  System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) +72
  System.Web.UI.Control.Render(HtmlTextWriter writer) +7
  System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +243
  System.Web.UI.Page.ProcessRequestMain() +1929