shares-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 Debian possible default full paths are:

/usr/bin/shares-admin - from package: gnome-system-tools

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

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