irexec: 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/irexec - from package: lirc

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

On Debian possible default full paths are:

/usr/bin/irexec - from package: lirc

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

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