sbuild-shell: 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-shell - from package: sbuild

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

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