wdf: 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/wdf - from package: wit

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

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