PHP下传图片出错：没有权限

<?php<br />
if ((($_FILES["file"]["type"] == "image/gif")<br />
|| ($_FILES["file"]["type"] == "image/jpeg")<br />
|| ($_FILES["file"]["type"] == "image/pjpeg"))<br />
&& ($_FILES["file"]["size"] < 20000))<br />
  {<br />
  if ($_FILES["file"]["error"] > 0)<br />
    {<br />
    echo "Return Code: " . $_FILES["file"]["error"] . "<br />";<br />
    }<br />
  else<br />
    {<br />
    echo "Upload: " . $_FILES["file"]["name"] . "<br />";<br />
    echo "Type: " . $_FILES["file"]["type"] . "<br />";<br />
    echo "Size: " . ($_FILES["file"]["size"] / 1024) . " Kb<br />";<br />
    echo "Temp file: " . $_FILES["file"]["tmp_name"] . "<br />";<br />
<br />
    if (file_exists("upload/" . $_FILES["file"]["name"]))<br />
      {<br />
      echo $_FILES["file"]["name"] . " already exists. ";<br />
      }<br />
    else<br />
      {<br />
      move_uploaded_file($_FILES["file"]["tmp_name"],"upload/" . $_FILES["file"]["name"]);<br />
      echo "Stored in: " . "upload/" . $_FILES["file"]["name"];<br />
      }<br />
    }<br />
  }<br />
else<br />
  {<br />
  echo "Invalid file";<br />
  }<br />
?>