textBox1.Text = webBrowser1.Document.Body.InnerText ---not working

private void Form1_Load(object sender, EventArgs e)
{
    webBrowser1.ScriptErrorsSuppressed = true;
    webBrowser1.Navigate(@"D:\Programe\Info\Visual Studio 2010\Projects\RussianAlfabet\RussianAlfabet\bin\Debug\acceptable.word");
    
    try
    {
        textBox1.Text = webBrowser1.Document.Body.InnerText; // ---not working
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message);   //Object reference not set to an instance of an object.
    }
//My webBrowser1 display the page all right, but the textbox1 is not displaying anything because of this error.

}