cgroupfs-umount: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/cgroupfs-umount - from package: cgroupfs-mount

You may install the required package with command apt-get install {package}

Error in other languages:
cgroupfs-umount: bevel nie gevind nie
cgroupfs-umount: comandă negăsită
cgroupfs-umount: comando não encontrado
cgroupfs-umount: commande introuvable
cgroupfs-umount: command not found
cgroupfs-umount: käsku ei ole
cgroupfs-umount: không tìm thấy lệnh
cgroupfs-umount: komanda nerasta
cgroupfs-umount: Kommando nicht gefunden.
cgroupfs-umount: kommandot finns inte
cgroupfs-umount: komut yok
cgroupfs-umount: nie znaleziono polecenia
cgroupfs-umount: níor aimsíodh an t-ordú
cgroupfs-umount: no se encontró la orden
cgroupfs-umount: no s'ha trobat l'ordre
cgroupfs-umount: opdracht niet gevonden
cgroupfs-umount: parancs nem található
cgroupfs-umount: perintah tidak ditemukan
cgroupfs-umount: príkaz nenájdený
cgroupfs-umount: příkaz nenalezen
cgroupfs-umount: команда не найдена
cgroupfs-umount: командата не е открита
cgroupfs-umount: 命令找不到
cgroupfs-umount: コマンドが見つかりません