pkcomposite: 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/pkcomposite - from package: pktools

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

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