irkerd: 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/irkerd - from package: irker

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