issues with amazon registry?

i'm registered at amazon and love it ... but i've heard from 2 different people now (both are very computer literate) that they couldn't purchase things off of my amazon registry ... amazon showed some sort of error about not knowing my address and since they didn't know it either, they couldn't purchase from there.

amazon has a little checkbox that allows 3rd party merchants to 'see' my address ... that checkbox is checked so i'm not sure what's going on ...

has anyone else had this issue?