jay: 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/jay - from package: mono-jay

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

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