darksnow: 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/darksnow - from package: darksnow

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

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