I have the same issue, recently I had a friend request .... I know, strange for me(HawaiiAl is my only friend and that's because I paid him to be my friend - it was done under the old system), under my settings/profile I had friends set to show friends and enabled, manually friend requests(or whatever the screen drop down box says). I get a personal conversation saying someone wanted to be my friend and I had to click the manage friends link to activate(that was the only option the screen dialog gave me). So, I click on it and nothing happened. I have since changed this setting to disabled, automatically add friends but haven't had a friend request to see if that fixed it.
I am not forum savvy and only do the very basics post in selective areas of topics -no chatting or blogging. Only use facebook because my sister said she was uploading pictures of her kids and grandchildren and she thought I would like to see them but all I seem to get are things like baby betty had her first hard pooh, little mary woke up at 3am, little tommy farted and it scared him, real meaningful things like that. I have another facebook friend(no, aquaintance) that belongs everyone of those silly groups and I had to delete any posting from that person because it was filling my entire page with junk. I signed up for a Linkedin account because a friend asks me to post a good reference for him and the only people that have viewed my link are people from my former employer monitoring to see if I joined any of their competitors, I guess.