"Add subscription" tab missing under "My account"

Hi all,

I have a problem and I can't find how to fix it. When a user goes to "Notifications tab" under "My account" the "add subscription" tab doesn't appear. He can see "Vista general" (sorry, I don't know which option is in english), "Subscriptions", "Author", "Type of content", but he doesn't any option to add a subscription (see attach1)

I've checked permissions, and I think all is how it has to be to "logged in users" (see attach2).

Any help?