refdb-restore: 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/refdb-restore - from package: refdb-clients

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

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