dwm.default: 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/dwm.default - from package: dwm

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

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