In Windows Vista SP1 or Windows Server 2008, when you try to play a video by using embedded RealNetworks RealPlayer 11 in Internet Explorer 8 Beta, you are prompted to download RealPlayer even though RealPlayer is successfully installed
On a Windows Vista SP1-based computer or on a Windows Server 2008-based computer, you visit a Web page by using Internet Explorer 8 Beta. When you try to play a video in this Web page by using embedded RealNetworks RealPlayer 11, you receive the following message even though RealPlayer has been installed successfully on the computer:
In order to play this video, you need the current version of RealPlayer.
Please click below to download the free RealPlayer.
Note: This problem does not occur if the computer is running the release-to-market (RTM) version of Windows Vista.
For more information on this issue, including potential causes, workarounds, and resolutions, see: Microsoft KB Article KB957055.