dul-web: 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/dul-web - from package: python-dulwich

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

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