pamstretch: 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/pamstretch - from package: netpbm-progs

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

On Debian possible default full paths are:

/usr/bin/pamstretch - from package: netpbm

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

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