Macromedia flash player

Hello,
My name is Chase and I am facing a really serious problem with Flash Player. I have tried to install it on my computer (I am currently using Windows Vista if this can help in any case...) and the message I keep on having is "You must install a later version of the Macromedia Flash Player". This is really annoying as I am a Web Designer and need this program promptly.
I will be very grateful if someone could tell me what to do.