irkbd: 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 CentOS possible default full paths are:

/usr/bin/irkbd - from package: irda-utils

You may install the required package with command yum install {package}

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