dgnova: 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/dgnova - from package: simh

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

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