Can’t install as user root
Running the installer as root is strongly discouraged.
Bugs in the installer have previously caused loss of data for people who ran it as root.
It is recommended to run it as a normal user as it doesn’t need further permissions.
We recommend you to install PocketMine-MP as a normal user, not as root. Create one if you don’t have one.
useradd -d /home/pocketmine -m pocketmine passwd pocketmine