imgur OAuth Error

<?php
    include_once "oauth-php/library/OAuthStore.php";
    include_once "oauth-php/library/OAuthRequester.php";

    define("IMGUR_CONSUMER_KEY", "xxx");
    define("IMGUR_CONSUMER_SECRET", "yyy");

    define("IMGUR_OAUTH_HOST","http://api.imgur.com");
    define("IMGUR_REQUEST_TOKEN_URL", IMGUR_OAUTH_HOST . "/oauth/request_token");
    define("IMGUR_AUTHORIZE_URL", IMGUR_OAUTH_HOST ."/oauth/authorize");
    define("IMGUR_ACCESS_TOKEN_URL", IMGUR_OAUTH_HOST ."/oauth/access_token");
    define("IMGUR_UPLOAD_URL", IMGUR_OAUTH_HOST ."/2/account/images");


    $options = array('consumer_key' => IMGUR_CONSUMER_KEY, 'consumer_secret' => IMGUR_CONSUMER_SECRET);

    OAuthStore::instance("2Leg",$options);

    try
    {
        $request = new OAuthRequester(IMGUR_REQUEST_TOKEN_URL, "POST");
        $result = $request->doRequest(0);
        parse_str($result['body'], $params);

        $filename = "image.jpg";
        $handle = fopen($filename, "r");
        $data = fread($handle, filesize($filename));

        // $data is file data
        $pvars   = array('image' => base64_encode($data), 'key' => $params["oauth_token"]);
        $timeout = 30;
        $curl    = curl_init();

        curl_setopt($curl, CURLOPT_URL, IMGUR_UPLOAD_URL);
        curl_setopt($curl, CURLOPT_TIMEOUT, $timeout);
        curl_setopt($curl, CURLOPT_POST, 1);
        curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
        curl_setopt($curl, CURLOPT_POSTFIELDS, $pvars);

        curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);


        //oauth_verifier

        $request_upload_2 = new OAuthRequester(IMGUR_UPLOAD_URL,"PUT",$params);
        $result_upload_2 = $request_upload_2->doRequest(0, $curl);

    }
    catch(OAuthException2 $e)
    {
         echo "Exception" . $e->getMessage();
    }