gmdb2: 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/bin/gmdb2 - from package: mdbtools-gui

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

On Debian possible default full paths are:

/usr/bin/gmdb2 - from package: mdbtools-gmdb

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

Error in other languages:
gmdb2: bevel nie gevind nie
gmdb2: comandă negăsită
gmdb2: comando não encontrado
gmdb2: commande introuvable
gmdb2: command not found
gmdb2: käsku ei ole
gmdb2: không tìm thấy lệnh
gmdb2: komanda nerasta
gmdb2: Kommando nicht gefunden.
gmdb2: kommandot finns inte
gmdb2: komut yok
gmdb2: nie znaleziono polecenia
gmdb2: níor aimsíodh an t-ordú
gmdb2: no se encontró la orden
gmdb2: no s'ha trobat l'ordre
gmdb2: opdracht niet gevonden
gmdb2: parancs nem található
gmdb2: perintah tidak ditemukan
gmdb2: príkaz nenájdený
gmdb2: příkaz nenalezen
gmdb2: команда не найдена
gmdb2: командата не е открита
gmdb2: 命令找不到
gmdb2: コマンドが見つかりません