The first time you make a gadget for Hyves you do need approval to be able to make the gadget "Live", which means that other users can install the gadget.

To do this you need OpenSocial Developer status (see this link).

When your gadget is approved you will receive OpenSocial Developer status. With that you will be able to set a certain amount of gadgets Live. You do not need approval for the other gadgets you set Live within the allocated amount of space.