Right-click on RagniteRO.exe and tick the box next to Run as Administrator.
Right-click on RagniteRO.exe and set its Compatibility mode to Windows XP (Service Pack 3).
Right-click on RagniteRO Patcher.exe and tick the box next to Run as Administrator.
Make sure the game is NOT installed in Program Files, My Documents or Desktop.
Example: C:\Ragnarok\
Disable Antivirus and Firewall software before installing and patching the client.