wait4amd: 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/wait4amd - from package: am-utils

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

Error in other languages:
wait4amd: bevel nie gevind nie
wait4amd: comandă negăsită
wait4amd: comando não encontrado
wait4amd: commande introuvable
wait4amd: command not found
wait4amd: käsku ei ole
wait4amd: không tìm thấy lệnh
wait4amd: komanda nerasta
wait4amd: Kommando nicht gefunden.
wait4amd: kommandot finns inte
wait4amd: komut yok
wait4amd: nie znaleziono polecenia
wait4amd: níor aimsíodh an t-ordú
wait4amd: no se encontró la orden
wait4amd: no s'ha trobat l'ordre
wait4amd: opdracht niet gevonden
wait4amd: parancs nem található
wait4amd: perintah tidak ditemukan
wait4amd: príkaz nenájdený
wait4amd: příkaz nenalezen
wait4amd: команда не найдена
wait4amd: командата не е открита
wait4amd: 命令找不到
wait4amd: コマンドが見つかりません