For whatever the reason may be, that link at the time of my writing, does not activate any playable .ram audio stream.
May I suggest another way to test if your MC can play a ".ra" or a ".ram" file?
1. Go to the RTHK web site: http://www.rthk.org.hk/rthk/download/news.html
2. Right click on one of the five DOWNLOAD icons and choose Save link as. (Two of them are for the Hong Kong news in Cantonese, and another is for the news in Mandarin. The remaining two are clearly marked as being for the news in English)
3. Save the link to your desktop.
4. Right click on the .ra file that you downloaded to your desktop and elect to open with Media Center.
Note: My MC can play all five of those downloadable ".ra" files, so this confirms that MC can play .ra files.
However - while I do not have Real Player installed in my system - I do have the Real Alternative player installed in my system. Therefore, due to the fact that I installed the Real Alternative player, I do have a RealAudio codec(s) within my system.
If it is a requirement to first have the RealAudio codec(s) in your system before MC can play .ra/.ram files, you can elect to do this by: installing a recommended, non-problem causing codec package or by installing any of several media players that are known to play RealAudio files (Real Player, Real Alternative, VLC Media Player, etc)