cURL is not able to upload file on scribd
<?php
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_HEADER, 0);
    curl_setopt($ch, CURLOPT_VERBOSE, 0);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_USERAGENT, "Mozilla/4.0 (compatible;)");
    curl_setopt($ch, CURLOPT_URL, _'http://www.scribd.com/upload/supload');
    curl_setopt($ch, CURLOPT_POST, true);
    // same as <input type="file" name="file_box">
    $post = array(
    $path=getcwd(); //absolute path
    $post = array(
        "file"=>"@".$path."/test.txt",
    );
    curl_setopt($ch, CURLOPT_POSTFIELDS, $post);
    $response = curl_exec($ch);
?>

$response = curl_exec($ch);
if ($response === false) {
   die(curl_error($ch));
}