git-dch: 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/git-dch - from package: git-buildpackage

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

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