Have you been receiving a PhysX error? Here are a few things you could try to resolve this issue:
Install using the PhysX Installer in the RO2 Folder
First, uninstall PhysX completely. Then, navigate to your Ragnarok Online 2 directory (either Steam\SteamApps\common\Ragnarok Online 2\ or Program Files (x86)\Gravity\Ragnarok Online 2). Inside the folder should be a PhysX installer. Please use this installer instead for PhysX. It may resolve the errors you are receiving due to PhysX.
Install using an older version of PhysX
If you're using the latest version of PhysX and it still gives you errors, try uninstalling that version and installing an older version of PhysX, found here
If you find that neither of these solutions are solving your issue, please submit a ticket
so we can investigate!