3dtopos: 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
/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/3dtopos - from package: survex

You may install the required package with command apt-get install {package}
Error in other languages:
3dtopos: bevel nie gevind nie
3dtopos: comandă negăsită
3dtopos: comando não encontrado
3dtopos: commande introuvable
3dtopos: command not found
3dtopos: käsku ei ole
3dtopos: không tìm thấy lệnh
3dtopos: komanda nerasta
3dtopos: Kommando nicht gefunden.
3dtopos: kommandot finns inte
3dtopos: komut yok
3dtopos: nie znaleziono polecenia
3dtopos: níor aimsíodh an t-ordú
3dtopos: no se encontró la orden
3dtopos: no s'ha trobat l'ordre
3dtopos: opdracht niet gevonden
3dtopos: parancs nem található
3dtopos: perintah tidak ditemukan
3dtopos: príkaz nenájdený
3dtopos: příkaz nenalezen
3dtopos: команда не найдена
3dtopos: командата не е открита
3dtopos: 命令找不到
3dtopos: コマンドが見つかりません