pnmpad: 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/pnmpad - from package: netpbm-progs

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

On Debian possible default full paths are:

/usr/bin/pnmpad - from package: netpbm

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

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