pdksh: 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:

/bin/pdksh - from package: pdksh

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

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