fil opload

--- Upload.htm ---
<form method="post" enctype="multipart/form-data" action="./Upload.php">
<input type="hidden" name="MAX_FILE_SIZE" value="1024"><input type="file" name="file">
<input type="submit" value=" - O p l o a d - ">
</form>

--- Upload.php ---
if (is_uploaded_file($_FILES['file']['tmp_name']))
  copy($_FILES['file']['tmp_name'], "d:\\tmp\\");
else
  echo "Possible file upload attack. Filename: " . $_FILES['file']['name'];

når jeg prøver at oploade en fil får jeg beskeden Possible file upload attack. Filename: filnavn
hvorfor virker scriptet ikke?!