sbuild-apt: 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/sbuild-apt - from package: sbuild

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

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