how to give the permeation to allow the STA threads in IIS

public partial class Test : Page
{
    bool snap = false;
    protected void CreateThumbnailImage(object sender, EventArgs e)
    {            
        snap = true;
    }
    protected override void Render(HtmlTextWriter writer)
    {
        if (snap)
        {
            int width = Int32.Parse(txtWidth.Text);
            int height = Int32.Parse(txtHeight.Text);
            StringBuilder builder = new StringBuilder();
            HtmlTextWriter htw = new HtmlTextWriter(new StringWriter(builder));
            base.Render(htw);
            string html = builder.ToString();
            Thumbnail thumbnail = new Thumbnail(html, 800, 600, width, height, Thumbnail.ThumbnailMethod.Html);
            Bitmap image = thumbnail.GenerateThumbnail();
            image.Save(Server.MapPath("~") + "/Thumbnail.bmp");                
            writer.Write(html);
            writer.Write("<img src=\"Thumbnail.bmp\" />");
        }
        else
            base.Render(writer);
    }
}
public class Thumbnail
{
    public enum ThumbnailMethod { Url, Html };
    public string Url { get; set; }
    public Bitmap ThumbnailImage { get; set; }
    public int Width { get; set; }
    public int Height { get; set; }
    public int BrowserWidth { get; set; }
    public int BrowserHeight { get; set; }
    public string Html { get; set; }
    public ThumbnailMethod Method { get; set; }
 
    public Thumbnail(string data, int browserWidth, int browserHeight, int thumbnailWidth, 
                                    int thumbnailHeight, ThumbnailMethod method)
    {
        this.Method = method;
        if (method == ThumbnailMethod.Url)
            this.Url = data;
        else if (method == ThumbnailMethod.Html)
            this.Html = data;
        this.BrowserWidth = browserWidth;
        this.BrowserHeight = browserHeight;
        this.Height = thumbnailHeight;
        this.Width = thumbnailWidth;
    }
    public Bitmap GenerateThumbnail()
    {
        Thread thread = new Thread(new ThreadStart(GenerateThumbnailInteral));
        thread.SetApartmentState(ApartmentState.STA);
        thread.Start();
        thread.Join();
        return ThumbnailImage;
    }
    private void GenerateThumbnailInteral()
    {
        WebBrowser webBrowser = new WebBrowser();
        webBrowser.ScrollBarsEnabled = false;
        if (this.Method == ThumbnailMethod.Url)
            webBrowser.Navigate(this.Url);
        else webBrowser.DocumentText = this.Html;
        webBrowser.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(WebBrowser_DocumentCompleted);
        while (webBrowser.ReadyState != WebBrowserReadyState.Complete) Application.DoEvents();
        webBrowser.Dispose();
    }
    private void WebBrowser_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
    {
        WebBrowser webBrowser = (WebBrowser)sender;
        webBrowser.ClientSize = new Size(this.BrowserWidth, this.BrowserHeight);
        webBrowser.ScrollBarsEnabled = false;
        this.ThumbnailImage = new Bitmap(webBrowser.Bounds.Width, webBrowser.Bounds.Height);
        webBrowser.BringToFront();
        webBrowser.DrawToBitmap(ThumbnailImage, webBrowser.Bounds);
        this.ThumbnailImage = (Bitmap)ThumbnailImage.GetThumbnailImage(Width, Height, null, IntPtr.Zero);
    }
}