Some studios require you to redeem Ultraviolet (UV Codes) using customized website, provided on the UV Code. In order to watch the movie on Vudu, you must have the same Ultraviolet Account linked to your Vudu account.
Basic Steps:
1) Login at Vudu.com
2) In the top right hand corner you will see your "Name" or Account Name.
3) Bring up the drop down menu, and visit "Ultraviolet" menu item.
*If you have already Linked your UV account, you will see the details of the linked account here.
4) If you have not yet linked a UV account you will see the option "Create Ultraviolet Library" or "Already have Ultraviolet?", be sure to click "Already have Ultraviolet". Use the same Ultraviolet Account with all providers, and studios in order to see your entire collection from cloud to cloud.