Rookie cannot upload txt file with php

Rookie cannot upload txt file with php

I am using the following php file,
<?php
if ($_FILES["file"]["error"] > 0)
{
echo "Error: " . $_FILES["file"]["error"] . "<br>";
}
else
{
echo "Upload: " . $_FILES["file"]["name"] . "<br>";
echo "Type: " . $_FILES["file"]["type"] . "<br>";
echo "Size: " . ($_FILES["file"]["size"] / 1024) . " kB<br>";
echo "Stored in: " . $_FILES["file"]["tmp_name"];
}
$uploaddir = '/var/www/setup/upload';
$uploadfile = $uploaddir . basename($_FILES['file']['name']);
echo '<pre>';
if (move_uploaded_file($_FILES['file']['tmp_name'], $uploadfile)) {
echo "File is valid, and was successfully uploaded.\n";
} else {
echo "Possible file upload attack!\n";
}
echo 'Here is some more debugging info:';
print_r($_FILES);
print "</pre>";
?>
So, I cannot upload file. I would appreciate any hint , Thanks in advance :-)