ppmtopuzz: 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/ppmtopuzz - from package: netpbm-progs

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

On Debian possible default full paths are:

/usr/bin/ppmtopuzz - from package: netpbm

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

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