I have a class as following

public class ScheduledUpdater
{
    private static Queue<int> PendingIDs = new Queue<int>();
    private static bool UpdateThreadRunning = false;
    private static bool IsGetAndSaveScheduledUpdateRunning = false;
    private static DataTable ScheduleConfiguration;
    private static Thread updateRefTableThread;
    private static Thread threadToGetAndSaveScheduledUpdate;
    public static void ProcessScheduledUpdates(int ID)
    {
        //do some stuff
        // if ( updateRefTableThread not already running)
        // execute updateRefTableThread = new Thread(new ThreadStart(UpdateSchedulingRefTableInThrear));
        // execute updateRefTableThread.Start();
        //do  some stuff
        GetAndSaveScheduledUpdate(ID)
    }
    private static void UpdateSchedulingRefTableInThrear()
    {
        UpdateSchedulingRefTable();
    }
    public static void UpdateSchedulingRefTable()
    { 
        // read DB and update ScheduleConfiguration 
        string query = " SELECT ID,TimeToSendEmail FROM TBLa WHERE MODE = 'WebServiceOrder' AND BDELETE = false ";
        clsCommandBuilder commandBuilder = new clsCommandBuilder();
        DataSet ds = commandBuilder.GetDataSet(query);
        if (ds != null && ds.Tables.Count > 0 && ds.Tables[0].Rows.Count > 0)
        {
            List<string> lstIDs = new List<string>();
            for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
            {
                lstIDs.Add(ds.Tables[0].Rows[i]["ID"].ToString());
                if (LastEmailSend.Contains(ds.Tables[0].Rows[i]["ID"].ToString()))
                    LastEmailSend[ds.Tables[0].Rows[i]["ID"].ToString()] = ds.Tables[0].Rows[i]["TimeToSendEmail"].ToString();
                else
                    LastEmailSend.Add(ds.Tables[0].Rows[i]["ID"].ToString(), ds.Tables[0].Rows[i]["TimeToSendEmail"].ToString());
            }
            if (lstIDs.Count > 0)
            {
                string Ids = string.Join(",", lstIDs.ToArray()).Trim(',');
                dhDBNames dbNames = new dhDBNames();
                dbNames.Default_DB_Name = dbNames.ControlDB;
                dhGeneralPurpose dhGeneral = new dhGeneralPurpose();
                dhGeneral.StringDH = Ids;
                DataSet result = commandBuilder.GetDataSet(dbNames, (object)dhGeneral, "xmlGetConfigurations");
                if (result != null && result.Tables.Count > 0)
                {
                    if (ScheduleConfiguration != null)
                        ScheduleConfiguration.Clear();
                    ScheduleConfiguration = result.Tables[0];
                }
            }
        }
    }
    public static void GetAndSaveScheduledUpdate(int ID)
    {
        //use ScheduleConfiguration 
        if (ScheduleConfiguration == null)[1]
            UpdateSchedulingRefTable();
        DataRow[] result = ScheduleConfiguration.Select("ID = "+ID);
        //then for each result row, i add this to a static Queue PendingIDs

    }
}

The function UpdateSchedulingRefTable can be called any time from outside world (for instance if someone updates the schedule configuration manually) ProcessScheduledUpdates is called from a windows service every other minute. Problem: Datatable ScheduleConfiguration is updated in the UpdateSchedulingRefTable (called from outside world - say manually) but when i try to use Datatable ScheduleConfiguration in GetAndSaveScheduledUpdate, i get the older version of values....

What am I missing in this stuff???

About EDIT: I thought the stuff i have not shown is quite obvious and possibly not desired, perhaps my structure is wrong :) and sorry for incorrect code previously, i made a simple function call as a thread initialization... sorry for my code indentation too because i don't know how to format whole block...