"Add Friend" button missing next to a person on Facebook, we have mutual friends?

[Vic]

I was friends with a girl on Facebook for sometime, I unfriended her later because of few issues.
Then again I sent her a FB friend request and she didn't approve it for few weeks and her profile
kept saying "Friend Request Sent", then again I cancelled this request since she hasn't approved it.
She is active btw on FB between my requests.
Now I don't get the Add Friend button next to her profile, we have 3-4 mutual friends.
I am able to view her public profile while logged into FB, guess she has not blocked me.
How do I send her a friend request again ? I don't want to ask in person.

[Tim Tebow here]

Your last sentence is the problem with fb. You need to get your face out of the computer and go live life. Stop using fb. Its a stupid waste of time. A REAL women wouldn't want you using that crap. So quit being a girl and go play a sport or clean the yard.

[NOOOO]

She may have blocked people from adding her.
If she didn't accept your request the first time and she's very active on the site I would assume she doesn't want you on there, sorry.

[Harry Potter..]

When u ignore a friend request fb asks u if u now the person in reall.. Its her wish.. U cannot do anything.. Just message her.. Talk to her.. And ask her to send u friend request.. No other way..