git-buildpackage: 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-buildpackage - from package: git-buildpackage

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

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