sensible-browser: 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/sensible-browser - from package: sensible-utils

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

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