A1). No, you do not need to register the client modules for things to work. The server(s) auto-detect new stores when they first connect. This starts the 60 day trial period.
A2). Without a doubt, the biggest cause for the module to not work ‘out of the box’ is due to the absence of a valid postcode for your store. This is NOT a setting that can be done via the ozpost module settings. This is a storewide setting that should have been defined when you first set up your store and provided the store name and address details. The exact location for these settings is dependent of the store software that you are using.
A3). The other most common reason for quotes to not be returned is if the parcel being quoted doesn’t have any weights or dimensions assigned to it. None of the supported carriers will provide a quote for items that apparently don’t weigh anything and take zero space.
A4) See A2 & A3. If you still have a problem please contact us.