am-eject: 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/sbin/am-eject - from package: am-utils

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

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