From the page you referenced, to download the player for .arf files for windows, I get this link:
https://welcome.webex.com/client/wbxclient/nbr2player.msi
To download the player for .wrf files for windows, I get this link:
https://welcome.webex.com/client/wbxclient/atrecply.msi
If that's still not working for you, you can download the players from your own webex site. Log in and go to Meeting Center, Support / Downloads, then click the Recorder and Players link and you'll see the link to download the .arf player. On my site, the link to download the .arf player for windows is this:
https://akamaicdn.webex.com/client/WBXclient-T28L10NSP1-321/nbr2player.msi
I hope this helps.
Susan McEvilly
Meet Me In The Cloud, LLC