warning curl_close()

I am getting Warning: curl_close(): supplied argument is not a valid cURL handle resource in \path\ on line 123

In the line the following code is present.

public function stopPlugin($graceful=false)
    {
    if ($this->settings['transport']=='curl')
        curl_close($this->curl);
    if (!$graceful) if (file_exists($this->cookie)) unlink($this->cookie);
    }

I got this开发者_开发问答 error while using Open Inviter script Please help me to how to fix this error.

$this->curl is empty or not a valid json resource :)

try

var_dump($this->curl);

to get your resources