sweethome3d: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH

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/sweethome3d - from package: sweethome3d

You may install the required package with command apt-get install {package}
Error in other languages:
sweethome3d: bevel nie gevind nie
sweethome3d: comandă negăsită
sweethome3d: comando não encontrado
sweethome3d: commande introuvable
sweethome3d: command not found
sweethome3d: käsku ei ole
sweethome3d: không tìm thấy lệnh
sweethome3d: komanda nerasta
sweethome3d: Kommando nicht gefunden.
sweethome3d: kommandot finns inte
sweethome3d: komut yok
sweethome3d: nie znaleziono polecenia
sweethome3d: níor aimsíodh an t-ordú
sweethome3d: no se encontró la orden
sweethome3d: no s'ha trobat l'ordre
sweethome3d: opdracht niet gevonden
sweethome3d: parancs nem található
sweethome3d: perintah tidak ditemukan
sweethome3d: príkaz nenájdený
sweethome3d: příkaz nenalezen
sweethome3d: команда не найдена
sweethome3d: командата не е открита
sweethome3d: 命令找不到
sweethome3d: コマンドが見つかりません