debian-reference: 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/bin/debian-reference - from package: debian-reference-common

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

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