paulstretch: command not found

Have You tried accessing the binary with the full path?

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 Debian possible default full paths are:

/usr/bin/paulstretch - from package: paulstretch

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