setuidgid: command not found

Have You tried accessing the binary with the full path?

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/setuidgid - from package: daemontools

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