pkinfo: 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/pkinfo - from package: pktools

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

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