netsurf-fb: 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/netsurf-fb - from package: netsurf-fb

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