En warpportal un usuario dijo que se soluciona asi:
1. install iRO normally until i got the error message.
2. copy-paste the entire \Program Files\Gravity\Ragnarok Online folder to a different folder.
3. click [OK] to close the error message. This will delete the original install directory (\Gravity\Ragnarok)
4. move the copy-pasted folder to \Program Files
5. extract content of Media2.cab to \Gravity\Ragnarok folder.
6. play
