FTP details are requested when installing the theme/plugin.
The issue is connected with file permissions/ownership.
Please edit wp-config.php file and add the following lines:
define('FS_METHOD', 'direct'); define('FS_CHMOD_DIR', 0770); define('FS_CHMOD_FILE', 0660);
The screenshot shows where exactly it should be placed in the file: http://prntscr.com/ghshy3
In case you still have issues, please provide me with your Wordpress username/password and FTP details in the support ticket.