pamlookup: 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 CentOS possible default full paths are:

/usr/bin/pamlookup - from package: netpbm-progs

You may install the required package with command yum install {package}

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