debrsign: 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/debrsign - from package: devscripts

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

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