scrot: 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/scrot - from package: scrot

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