iagno: 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/iagno - from package: gnome-games

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

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