can't add someone as a friend.. please help...

Hello everyone, i want to add someone as a friend, the add friend button however is missing on her page.
I have another facebookpage on which the add friend button on her page does appear, i can invite her there to be friends with me, so she hasn't disabled the add friends button. This page however i dont wish to use.
When i checked if i might be blocked by her, i think i'm not for her name appears in the list of search results and i can also send her messages..

What is going on?
All help is welcome, thank you..