gmerlin_visualizer: 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/bin/gmerlin_visualizer - from package: gmerlin

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