gnumed: 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/gnumed - from package: gnumed-client

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

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