- You need two mods installing. Premium Membership and Payments. Current versions are 1.0.13 and 1.0.5 respectively. Did you install them through Automod or manually?
- Missing shopping.php. It's looking for the language file (the one in root is the process) and is part of the payment mod. Which version do you have?
- Premium Memberships. I wouldn't use Newly Registered or Registered as PhpBB maintains them and will find users appear and disappear. Create a new group, Premium Members and set that up with all of the permissions you want.
- Purchase Membership. You won't get the payments option until you click on the Purchase Membership button.
- Registration Information. The mod presents any custom profile fields that are prefixed with 'ms_'. I've created a few in the mod as examples but you can create new ones and delete any or all of them in the ACP Custom Profile Fields.
- Never. New users will not be presented with the option to upgrade to premium membership during registration. This is useful if you want to only offer premium membership to established users in your community.
- Optional. The user can decide during the registration process if they want to subscribe to the premium membership
- Always. Select this if you want to restrict the site to paying members.