pdmenu: 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/bin/pdmenu - from package: pdmenu

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

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