pkreclass: 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/pkreclass - from package: pktools

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

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