Error On Mozilla for client object model, while saving ' Request failed'

Hi,

following is my code, I am getting this error on runing this code ( it runs on a button save)

This works perfectly well in IE without error, problem only with mozilla

Request failed. Unexpected response from server. The status code of response is "0". The status text of response is ''.null

$("input[title='First Name']").removeClass("highlight");
 $("input[title='Last Name']").removeClass("highlight");
 /*************************************************/

    var FirstName=$("input[title='First Name']").val();
    //alert(FirstName);   

    var LastName= $("input[title='Last Name']").val();
    //alert(LastName);   


    var Notes= $("textarea[title='Notes/Special Instruction']").val();
    //alert(Notes);


     if(FirstName==''||FirstName==null)
    {
     $("input[title='First Name']").addClass("highlight");
    }
    if(LastName==''||LastName==null)
    {
      $("input[title='Last Name']").addClass("highlight");

    }
    if(FirstName==''||FirstName==null || LastName==''||LastName==null )
    {
    alert("Please complete the fields marked in red ");
    return;
    }
    else
    {



        /********************Update CI Item in SharePoint***********************/
        //ClearRegistation(ID);

        var clientContext =new SP.ClientContext.get_current();                                  
        var oList = clientContext.get_web().get_lists().getByTitle('Contact Information');                              
        this.oListItem = oList.getItemById(ID);    
        this.oListItem.set_item("FirstName",FirstName);
        this.oListItem.set_item("Title",LastName);
        this.oListItem.set_item("Notes_x002F_Special_x0020_Instru",Notes);
        this.oListItem.set_item("Adsales_x0020_Contact",ID);                   
        this.oListItem.set_item("IsRegistered","Yes");
       this.oListItem.set_item("RSVP","No");
      

        //this.oListItem.set_item("EID",value);
        this.oListItem.update();                    

        //clientContext.executeQueryAsync();
        clientContext.executeQueryAsync(Function.createDelegate(this, this.onQuerySucceeded), Function.createDelegate(this, this.onQueryFailed));




    }