What steps are you following? You should not have to modify anything in the ROGame.ini file for the webadmin. The below steps are taken from one of the above-referenced posts:
1. Stop Server from GS Control Panel
2. Use FTP Client or FTP in Windows Explorer to Modify files
3. OPEN: "ro2server.bat" - Remove: ?adminpass=123 - Save new file to server.
4. OPEN: "config/ROWeb.ini" - Find Code: bEnabled=false - Replace with: bEnabled=true - Save new file to server.
5. OPEN: "config/ROWebAdmin.ini" - Find Code: [WebAdmin.WebAdmin] - Below this code add the following line:
6. Save file and Restart your RO 2 Server. (This is done so ROMultiAdmin.ini gets created, if it does not appear you have not done the steps above correctly)
7. Once your server has successfully hosted the game, Stop the server again from Control Panel.
8. OPEN: "config/ROMultiAdmin.ini"
9. Find Code:[Admin MultiAdminData] - Replace everthing below this with the following if it is not shown exactly like below:
10. Save and Close your files and restart your RO2 Server.
11. In a web browser goto http://server
IP:Listen Port/ServerAdmin - Example: http://220.127.116.11:9021/ServerAdmin
(If you do not know, your ListenPort can be found in your ROWeb.ini file)
12. Default Username: Admin - Default Password: Admin (case sensative)
I would also suggest changing your password from the default. To do this:
13. Go to Administrators tab on the Left Hand menu (2nd from bottom)
14. Select Admin from the drop down box
15. Click on "Edit Administrator:
16. Change your Password to whatever you want
17. Confirm Password
18. Click Save
You might have to log back into the WebAdmin using your new Password. Looks a little daunting to do, but it is not as bad as it looks.