plackup: 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/plackup - from package: libplack-perl

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

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