move_uploaded_file错误6 php

Question

Attempting to move an uploaded file so that it is saved in the directory, it fails. I use echo ($_FILES['company_logo'] ['error']); to get the error number. The only place I could find with error numbers for this was http://www.htmlgoodies.com/beyond/php/article.php/3472561/PHP-Tutorial-Error-Handling.htm . However, their list only goes up to 4 and I am getting the error number 6. Does anyone know what this error stands for? Here is my code:

$allowed_filetypes = array('.jpg','.jpeg','.gif','.bmp','.png'); // These will be the types of file that will pass the validation.
$max_filesize = 524288; // Maximum filesize in BYTES (currently 0.5MB).
$upload_path = '../images/companies/'; // The place the files will be uploaded to (currently a 'files' directory).

if($_FILES['company_logo']['name'] != "") {
    if($row['image'] != ''){
        unlink("../".$row['image']);
    }

    $filename = $_FILES['company_logo']['name']; // Get the name of the file (including file extension).               
    $ext = substr($filename, strpos($filename,'.'), strlen($filename)-1); // Get the extension from the filename.
    $ext = strtolower($ext);
    // Check if the filetype is allowed, if not DIE and inform the user.
    if(!in_array($ext,$allowed_filetypes))
        die('The file you attempted to upload is not allowed.');

    // Now check the filesize, if it is too large then DIE and inform the user.
    if(filesize($_FILES['company_logo']['tmp_name']) > $max_filesize)
        die('The file you attempted to upload is too large.');

    // Check if we can upload to the specified path, if not DIE and inform the user.
    if(!is_writable($upload_path))
        die('You cannot upload to the specified directory, please CHMOD it to 777.');

      // Upload the file to your specified path.
    $ran = rand();
    $filename = $ran.$ext;
    if(move_uploaded_file($_FILES['company_logo']['tmp_name'],$upload_path.$filename)){  // This is where it fails
           $file = $upload_path.$filename;

           $result = mysql_query("UPDATE Companies SET image = 'images/companies/$filename' WHERE id = '$id';");                                                        

           if($result)
              $_SESSION['message'] .= "<p class='copy' style='color:red;'>Your image upload was successful.</p>"; // It worked.
           else
              $_SESSION['message'] .= "<p class='copy' style='color:red;'>Unable to upload image(s).</p>";
    }else{
           $_SESSION['message'] .= "<p class='copy' style='color:red;'>Unable to upload image(s).</p>";
           echo ($_FILES['company_logo'] ['error']);
            die();
    }
}

As you can see, I do check for an actual file being uploaded, if the file extension is in a list of file types allowed, if the file exceeds the max file size, and whether the path is even writable. So I don't believe it is any of those things, but I'm not certain. Any help would be appreciated.

Answer 1

PHP manual knows 99,99% answers.

UPLOAD_ERR_NO_TMP_DIR

Value: 6; Missing a temporary folder. Introduced in PHP 4.3.10 and PHP 5.0.3.