fex2bin: 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/fex2bin - from package: sunxi-tools

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

Error in other languages:
fex2bin: bevel nie gevind nie
fex2bin: comandă negăsită
fex2bin: comando não encontrado
fex2bin: commande introuvable
fex2bin: command not found
fex2bin: käsku ei ole
fex2bin: không tìm thấy lệnh
fex2bin: komanda nerasta
fex2bin: Kommando nicht gefunden.
fex2bin: kommandot finns inte
fex2bin: komut yok
fex2bin: nie znaleziono polecenia
fex2bin: níor aimsíodh an t-ordú
fex2bin: no se encontró la orden
fex2bin: no s'ha trobat l'ordre
fex2bin: opdracht niet gevonden
fex2bin: parancs nem található
fex2bin: perintah tidak ditemukan
fex2bin: príkaz nenájdený
fex2bin: příkaz nenalezen
fex2bin: команда не найдена
fex2bin: командата не е открита
fex2bin: 命令找不到
fex2bin: コマンドが見つかりません