Why am I getting this error:“Cross-thread operation not valid: Control lbFolders accessed from a thread other than the thread it was created on.”?

prgAll.Maximum = lbFolders.SelectedItems.Count;

foreach (string dir in lbFolders.SelectedItems)

lblStatus.Invoke((Action)(() => lblStatus.Text = counter.ToString()));

lblTest.Invoke((MethodInvoker)(delegate()
{
  lblTest.Text = i.ToString();
}));

prgAll.Maximum = lbFolders.SelectedItems.Count;

void SetMax()
{
    if (prgAll.InvokeRequired)
    {
        prgAll.BeginInvoke(new MethodInvoker(SetMax));
        return;
    }

    prgAll.Maximum = lbFolders.SelectedItems.Count;
}

private void RunMe()
{
    if (!InvokeRequired)
    {
        myLabel.Text = "You pushed the button!";
    }
    else
    {
        Invoke(new ThreadStart(RunMe));
    }
}