debuild-pbuilder: 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/debuild-pbuilder - from package: pbuilder

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

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