pd: 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 - from package: puredata-core

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

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