Sorry for the late reply guys,
I managed to do what I wanted to do, through the command emulator without any problems.
ES file explorer now updated to a newer version, but still have the same problem. Can't create a directory anywhere in the root or root folders.
Files are no problem. I tried different names of folders, nothing works...
What I did noticed is that when I try to create a file it says "superuser access granted" followed by "file created". When I try to create a folder it immediately says "sorry operation failed", and it doesn't say anything about superuser. I tried reinstall, cleared superuser data, nothing works.