gm-backup_data: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH

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/sbin/gm-backup_data - from package: gnumed-server

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