sbuild-clean: 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-clean - from package: sbuild

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

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