AirInvClient: 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/AirInvClient - from package: airinv

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

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