getseuser: command not found

Have You tried accessing the binary with the full path?

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/getseuser - from package: selinux-utils

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