unclutter: 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/unclutter - from package: unclutter

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

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