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/dch - from package: devscripts

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

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