gastables: 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/gastables - from package: gastables

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

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