postfix-nochroot: 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/sbin/postfix-nochroot - from package: selinux-basics

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

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