wmhdplop: 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/wmhdplop - from package: wmhdplop

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

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