dump-stl: 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/dump-stl - from package: slic3r

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

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