Entering just playonmac.com in a browser (I've tried safari and firefox, not that it matters) redirects a few times and ends up at www.playonmac.com/en/en - Page not found.
Note that while playponmac doesn't redirect correctly, playonlinux redirects fine.
Here's a cutdown example using curl.
$ curl -L -I http://playonmac.com/
HTTP/1.1 302 Found
Server: Apache
Pragma: no-cache
Location: en/
Vary: Accept-Encoding
Content-Type: text/html
HTTP/1.1 302 Found
Server: Apache
Pragma: no-cache
Location: en/
Vary: Accept-Encoding
Content-Type: text/html
HTTP/1.1 301 Moved Permanently
Server: Apache
Pragma: no-cache
Location: http://www.playonlinux.com/en/en/
Vary: Accept-Encoding
Content-Type: text/html
HTTP/1.1 404 Not Found
Server: Apache
Pragma: no-cache
Vary: Accept-Encoding
Content-Type: text/html