e-mails .... não consigo enviar .....

Server Error in '/' Application.--------------------------------------------------------------------------------The "SendUsing" configuration value is invalid. 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.Runtime.InteropServices.COMException: The "SendUsing" configuration value is invalid. Source Error: An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. Stack Trace: [COMException (0x80040220): The "SendUsing" configuration value is invalid.][TargetInvocationException: Exception has been thrown by the target of an invocation.] System.RuntimeType.InvokeDispMethod(String name, BindingFlags invokeAttr, Object target, Object[] args, Boolean[] byrefModifiers, Int32 culture, String[] namedParameters) +0 System.RuntimeType.InvokeMember(String name, BindingFlags invokeAttr, Binder binder, Object target, Object[] args, ParameterModifier[] modifiers, CultureInfo culture, String[] namedParameters) +473 System.Web.Mail.LateBoundAccessHelper.CallMethod(Object obj, String methodName, Object[] args) +58[HttpException (0x80004005): Could not access 'CDO.Message' object.] System.Web.Mail.LateBoundAccessHelper.CallMethod(Object obj, String methodName, Object[] args) +111 System.Web.Mail.CdoSysHelper.Send(MailMessage message) +1844 System.Web.Mail.SmtpMail.Send(MailMessage message) +153 FotoMais.Index.btnEnviar_Click(Object sender, EventArgs e) in D:\Filipe\Visual Studio 2k3 WebSites\FotoMais\Index.aspx.vb:64 System.Web.UI.WebControls.Button.OnClick(EventArgs e) +108 System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +57 System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +18 System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +33 System.Web.UI.Page.ProcessRequestMain() +1292 --------------------------------------------------------------------------------Version Information: Microsoft .NET Framework Version:1.1.4322.2300; ASP.NET Version:1.1.4322.2300