change statecode error

Hi All,

I wanted to change the statecode for case entity based on a optionset value. But i get the error : internal server error.

Here is my code, can anyone help me..

  function closeCall() { 
  var optionsetVal = Xrm.Page.data.entity.attributes.get("new_optionsetfield"); 
    OptionsetTextValue = optionsetVal.getSelectedOption().text;
    if (OptionsetTextValue == "Close") { 
    /*if (Xrm.Page.data.entity.getIsDirty()) {
        alert("Please save your changes before cancelling the appointment.");
        return;
    }*/
    // create the request
    var request = "<s:Envelope xmlns:s=\"http://schemas.xmlsoap.org/soap/envelope/\">";
    request += "<s:Body>";
    request += "<Execute xmlns=\"http://schemas.microsoft.com/xrm/2011/Contracts/Services\" xmlns:i=\"http://www.w3.org/2001/XMLSchema-instance\">";
    request += "<request i:type=\"b:SetStateRequest\" xmlns:a=\"http://schemas.microsoft.com/xrm/2011/Contracts\" xmlns:b=\"http://schemas.microsoft.com/crm/2011/Contracts\">";
    request += "<a:Parameters xmlns:c=\"http://schemas.datacontract.org/2004/07/System.Collections.Generic\">";
    request += "<a:KeyValuePairOfstringanyType>";
    request += "<c:key>EntityMoniker</c:key>";
    request += "<c:value i:type=\"a:EntityReference\">";
    request += "<a:Id>" + Xrm.Page.data.entity.getId() + "</a:Id>";
    request += "<a:LogicalName>incident</a:LogicalName>";
    request += "<a:Name i:nil=\"true\" />";
    request += "</c:value>";
    request += "</a:KeyValuePairOfstringanyType>";
    request += "<a:KeyValuePairOfstringanyType>";
    request += "<c:key>State</c:key>";
    request += "<c:value i:type=\"a:OptionSetValue\">";
    request += "<a:Value>1</a:Value>";
    request += "</c:value>";
    request += "</a:KeyValuePairOfstringanyType>";
    request += "</a:Parameters>";
    request += "<a:RequestId i:nil=\"true\" />";
    request += "<a:RequestName>SetState</a:RequestName>";
    request += "</request>";
    request += "</Execute>";
    request += "</s:Body>";
        request += "</s:Envelope>";
 
    //send set state request
    $.ajax({
        type: "POST",
        contentType: "text/xml; charset=utf-8",
        datatype: "xml",
        url: Xrm.Page.context.getServerUrl() + "/XRMServices/2011/Organization.svc/web",
        data: request,
        beforeSend: function (XMLHttpRequest) {
            XMLHttpRequest.setRequestHeader("Accept", "application/xml, text/xml, */*");
            XMLHttpRequest.setRequestHeader("SOAPAction", "http://schemas.microsoft.com/xrm/2011/Contracts/Services/IOrganizationService/Execute");
        },
        success: function (data, textStatus, XmlHttpRequest) {
            Xrm.Page.ui.close();
        },
        error: function (XMLHttpRequest, textStatus, errorThrown) {
            alert(errorThrown);
        }
    });    
}
}

thanks

Gary