xprintidle: 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/xprintidle - from package: xprintidle

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

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