aa-enforce: 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/aa-enforce - from package: apparmor-utils

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

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