jp2a: command not found

Have You tried accessing the binary with the full path?

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/jp2a - from package: jp2a

You may install the required package with command apt-get install {package}
Error in other languages:
jp2a: bevel nie gevind nie
jp2a: comandă negăsită
jp2a: comando não encontrado
jp2a: commande introuvable
jp2a: command not found
jp2a: käsku ei ole
jp2a: không tìm thấy lệnh
jp2a: komanda nerasta
jp2a: Kommando nicht gefunden.
jp2a: kommandot finns inte
jp2a: komut yok
jp2a: nie znaleziono polecenia
jp2a: níor aimsíodh an t-ordú
jp2a: no se encontró la orden
jp2a: no s'ha trobat l'ordre
jp2a: opdracht niet gevonden
jp2a: parancs nem található
jp2a: perintah tidak ditemukan
jp2a: príkaz nenájdený
jp2a: příkaz nenalezen
jp2a: команда не найдена
jp2a: командата не е открита
jp2a: 命令找不到
jp2a: コマンドが見つかりません