omxregister-bellagio: 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
/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/omxregister-bellagio - from package: libomxil-bellagio0

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