stonith_admin: 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/stonith_admin - from package: pacemaker

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

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