snmppower: 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/snmppower - from package: powerman

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

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