Codeigniter FTP下载无法正常工作

I am trying to download the file from webserver to Local computer using codeigniter FTP class. Here is my code.

$this->load->library('ftp');

$config['hostname'] = 'ftp.mysite.com';
$config['username'] = 'username';
$config['password'] = '******';
$config['port']     = 21;
$config['passive']  = FALSE;
$config['debug']    = TRUE;
$this->ftp->connect($config);
$server_path = '/home1/user/public_html/podio/download/my document file.docx';
$local_path = '/Users/shani/Desktop/downloads/my document file.docx';
$this->ftp->download($server_path, $local_path, 'ascii');

and i am getting this error Message: ftp_get(/Applications/MAMP/htdocs/podio-dash/downloads/file.docx): failed to open stream: No such file or directory The local directory is there with all its read and write permissions. Any help will be highly encouraged. Thanks in advance.