Heres the solution:
!!IMPORTANT!!
- You need administrator rights to follow this steps! If you're not an administrator, ask your parents for help.
- English isn't my native language, so I'm sorry if my grammar is a bit off from time to time ^^°
- This guide is based on Windows 7, but Windows 8 isn't that much different, I guess.
- Thanks Alvana, just because of your help I was able to create this!
1. Before installing anything open a command prompt by pressing + R , inserting "cmd" (without qoutes) and pressing enter
2. Type: net localgroup Users /add (and press enter)
3. Proceed with installation of Ragnarok Online 2
4. You are not done yet! Go to the installation folder. It's probably located in C:\Program Files (x86)\Gravity\
5. Right click on the "Ragnarok 2"-folder and select "Properties"
6. Go to Security-tab, press "Advanced", go to Owner-tab
7. Press Edit-button and select your user-profile
8. Click the bottom checkbox "Replace all child object permissions [...]" and apply the whole stuff
9. Open another command prompt (like you did during step 1)
10. Type: net localgroup Users /delete (and press enter)
11. Now you should be able to start Ragnarok Online 2! ^^
Edited by Sabishii1985, 18 April 2013 - 03:58 AM.