Form error

[kh99]

I created a plugin using hook location misc_start and this code:

if ($_REQUEST['do'] == 'form')
{
   require_once("includes/adminfunctions.php");
  $userid = 1;
  print_form_header('misc', 'banned&u=' . $userid);
  print_table_header("Ban a User");
  print_label_row("Ban: " . $username);
  print_select_row("Ban Length", 'banLength', array(24 => "1 Day", 48 => "2 Days", 72 => "3 Days", 168 => "1 Week", 336 => "2 Weeks", 720 => "1 Month", -1 => "Permanently"), $vbulletin->GPC['userid']);
  print_input_row("Ban Reason:", 'banreason');
  print_submit_row("Ban");
    exit;
}
if (strpos($_GET['do'], 'banned') === 0)
{
    echo "banned userid=" . $_REQUEST['userid'] . "<BR />\n";
    print_r($_GET);
    exit;
}

Then I go to url misc.php&do=form, then submit the form.

I think I'm going to try a non-vb test file and see if maybe some vb code is messing with $_GET[do].