No, if you have the ritual spell, and you cast it in front of the temple inside the forest near Tarkas during a full moon, you should get the door to open (you can tell there is a full moon because a symbol above the door appears). I just tested it and it worked, so I am not sure what could be the problem.
Viewing post in Caliross, The Shapeshifter's Legacy comments
Equipment doesn't appear in your regular inventory, but it should appear in the "charms" sub-section. Anyway, if you did everything right you should be able to equip it in the "accessory" section of your equipment page. If you checked already, maybe send me a link to your savefile, and I can try to figure out what went wrong.