powwow: command not found

Have You tried accessing the binary with the full path?

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/powwow - from package: powwow

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