ppmddumpfont: 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/ppmddumpfont - from package: netpbm-progs

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

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