Just FYI for any future people, I disabled Jagex Launcher to run as adminstrator. Right Click > Properties > Disable Run as administrator. This fixed it for me.
Has this been fixed? I am having this issue now?
Troubleshooting Steps:
Have cleared cache
Added exceptions to Antivirus FW - didnt work. Even uninstalled it
Folowed steps here. Same error as Hexx above - I am using Jagex launcher accounts.