pamtooctaveimg: 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/pamtooctaveimg - from package: netpbm-progs

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

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