delgroup: 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

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/delgroup - from package: adduser

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