lookupconfig: 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/lookupconfig - from package: lookup

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

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