if your Nin Online folder is located in Program Files (x86) and you got the Runtimes it as to be that the server is down. wait till server is up i guess.
http://www.crystalshire.com/downloads.php when the download is finish you only need to use the (Setup.exe) the rest isn't important. And if you have a 64bit system the game folder should be installed in Program Files (x86)