pk1sign: 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/pk1sign - from package: libnss3-tools

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

Error in other languages:
pk1sign: bevel nie gevind nie
pk1sign: comandă negăsită
pk1sign: comando não encontrado
pk1sign: commande introuvable
pk1sign: command not found
pk1sign: käsku ei ole
pk1sign: không tìm thấy lệnh
pk1sign: komanda nerasta
pk1sign: Kommando nicht gefunden.
pk1sign: kommandot finns inte
pk1sign: komut yok
pk1sign: nie znaleziono polecenia
pk1sign: níor aimsíodh an t-ordú
pk1sign: no se encontró la orden
pk1sign: no s'ha trobat l'ordre
pk1sign: opdracht niet gevonden
pk1sign: parancs nem található
pk1sign: perintah tidak ditemukan
pk1sign: príkaz nenájdený
pk1sign: příkaz nenalezen
pk1sign: команда не найдена
pk1sign: командата не е открита
pk1sign: 命令找不到
pk1sign: コマンドが見つかりません