xaylet: 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/xaylet - from package: aylet-gtk

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