Проблемма с потоками

....
static void Main(){
     Application.Run(new Form1()); }

private void InitializeComponent(){
....
this.labelTubeTCurr = new System.Windows.Forms.Label();
...
this.labelTubeTCurr.Text = "10.0";
...
this.Controls.Add(this.groupBoxRecognizingFrame);  ....  }

private void menuItemPlay_Click(object sender, EventArgs e){
            threadAVIFile = new Thread(new ThreadStart(MainAVIFile));
            threadAVIFile.Start();
//MainAVIFile();    }

private void MainAVIFile(){
    for (pos = 0; pos < countFrames; pos++){
        dTubeTCurr =  pos / countFrames;
        strTubeTCurr = string.Format("{0:F2}", dTubeTCurr);
        [COLOR="YellowGreen"]this.labelTubeTCurr.Text = strTubeTCurr;[/COLOR]