pd-watchdog: 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 Debian possible default full paths are:

/usr/lib/puredata/bin/pd-watchdog - from package: puredata-core

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

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