gm_ctl_client: 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/gm_ctl_client - from package: gnumed-client

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

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