[Amarinth]

Hmm ok, that's not anything I've seen before - the error message points to a config file in the Launcher direction, under --> C:\Program Files\NCSoft\Launcher\Config\Default

It's possible an error's crept in there, but the launcher may create a new default file if you remove the old one, so here's what I suggest trying first. Shut down the launcher completely, then go to that directory above and r-click on the NClauncher.config file and rename it to: NClauncher.config.backup

Then restart the launcher and see if it makes a difference.