It sounds like you have a third-party application interfering with the download, or you're downloading a fake Flash Player distrubtion from somewhere that is not adobe.com. (Always get Adobe software from adobe.com to ensure that it hasn't been tampered with.)
Can you post the link you're using to download the Flash Player?
If you want the beta, use: http://www.adobe.com/go/flashplayerbeta
If you want the standard release version, use http://get.adobe.com/flashplayer
I'm downloading from the OFFICIAL standard release site, but I have this exact problem, in fact it also says 47%
Then you should post in the standard release forum, not the beta forum.
Use the offline installer(s) from http://helpx.adobe.com/flash-player/kb/installation-problems-flash-player-windows.html#mai n-pars_header
[topic moved to Flash Player release forum]