Step#1: Download latest kRO Full installer
This installer contains a clean copy of the latest kRO Full files that require to run Ragnarok Online Servers. After downloading this you need to download the mini installer.
Step#2: Download PlayRagnarokZombie Mini Installer (2004 Server)
In the event you have a clean copy of the latest full kRO folder, you will only need to download the Mini Installer.
Mini-Installers will overwrite each other, please be careful.