Trouble with Registry

Im trying to put together a registry in my account and have been able to add one or two items to it, but the majority of things I click "Add to gift registry" for, don`t show up on the list. An item here or there will work but ive found MANY that dont

Write what you want on paper and call the 800 number

Not that big of a deal to me. I can live without it, but I wanted to just shed some light on the problem. Or maybe its just me, I dunno