pkascii2img: 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/pkascii2img - from package: pktools

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

Error in other languages:
pkascii2img: bevel nie gevind nie
pkascii2img: comandă negăsită
pkascii2img: comando não encontrado
pkascii2img: commande introuvable
pkascii2img: command not found
pkascii2img: käsku ei ole
pkascii2img: không tìm thấy lệnh
pkascii2img: komanda nerasta
pkascii2img: Kommando nicht gefunden.
pkascii2img: kommandot finns inte
pkascii2img: komut yok
pkascii2img: nie znaleziono polecenia
pkascii2img: níor aimsíodh an t-ordú
pkascii2img: no se encontró la orden
pkascii2img: no s'ha trobat l'ordre
pkascii2img: opdracht niet gevonden
pkascii2img: parancs nem található
pkascii2img: perintah tidak ditemukan
pkascii2img: príkaz nenájdený
pkascii2img: příkaz nenalezen
pkascii2img: команда не найдена
pkascii2img: командата не е открита
pkascii2img: 命令找不到
pkascii2img: コマンドが見つかりません