pbuilder-dist-simple: 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/pbuilder-dist-simple - from package: ubuntu-dev-tools

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

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