As far as I know referral is just a guarantee that you will be called back after they see your CV. It doesn't guarantee you getting hired. I've referred plenty of people and a lot of them never got hired or even failed the screening phone call.
It just means "hey, try out this guy" and they won't be throwing away your CV into the pile of hundreds of thousands of CVs they get every year. You still need to go through everything like everyone else.
