group_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/group_tool - from package: cman

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

On Debian possible default full paths are:

/usr/sbin/group_tool - from package: cman

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

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