fence_tool: 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/fence_tool - from package: cman

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

On Debian possible default full paths are:

/usr/sbin/fence_tool - from package: cman

You may install the required package with command apt-get install {package}

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