fatlabel: 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:

/sbin/fatlabel - from package: dosfstools

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

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