The BBC have a link for downloading Realplayer, and it is this one, try that
http://tinyurl.com/3xnnc
Maybe you are on a "dodgy" real player site (a lot of people are now setting up "look alike" sites that make you THINK you are downloading from the genuine site but are not.
For example if you search on "free Avast" the top hit in Google is avast.s0ftware-ukk.com (I have deliberately slightly misspelt the site name so nobody goes to it).
You may THINK this is the avast site but it is not, Going to it brings up a virus warning (from avast funnyily enough).