debchange: 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/debchange - from package: devscripts

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

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