mountinfo: 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:

/lib/rc/bin/mountinfo - from package: openrc

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

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