Soundcloud: The requested URL responded with HTTP code 0
It's hard to debug this exception without seeing the source code. But my guess is that your problem might be related to this issue:
https://github.com/mptre/php-soundcloud/issues/3
Which means that you should modify your accessToken call and include the extra cURL parameters.
$accessToken = $soundcloud->accessToken($code, $postData, array( CURLOPT_SSL_VERIFYPEER => false, CURLOPT_SSL_VERIFYHOST => false,));
A much better solution would be to follow the answer listed on the following answer to Twitter API returns NULL on XAMPP which states that you should update the CA root certifications for your PHP solution.
For more information: