I was able to take ownership of the directory via the security tab and then delete them when it happened to me, but there are quite a few steps to follow.
It might be faster and simpler to just download PSO2 Tweaker launcher and run the permissions fix from its Troubleshooting window. You should be able to uninstall afterward, and then reinstall using Tweaker.
After that, apply the lobby lag fix from the Troubleshooting window, and you should be good to go. Just be sure to follow the instructions on the Arks-Layer website (the one from which you can download the Tweaker), and you should be fine.