These don't look correct. They would normally be /store/:
Code:
  define('DIR_WS_CATALOG', 'www.mydomain.com/store/');
  define('DIR_WS_HTTPS_CATALOG', 'www.mydomain.com/store/');
The ./../ is definitely incorrect here. It should be the actual filesystem path to your /store/ folder:
Code:
// * DIR_FS_* = Filesystem directories (local/physical)
  //the following path is a COMPLETE path to your Zen Cart files. eg: /var/www/vhost/accountname/public_html/store/
  define('DIR_FS_CATALOG', './../');

  define('DIR_FS_SQL_CACHE', './../cache');
Who are you hosted with?