ogmmerge: 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/ogmmerge - from package: ogmtools

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