decode_to_md5: 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 CentOS possible default full paths are:

/usr/bin/decode_to_md5 - from package: libvpx-utils

You may install the required package with command yum install {package}

Error in other languages:
decode_to_md5: bevel nie gevind nie
decode_to_md5: comandă negăsită
decode_to_md5: comando não encontrado
decode_to_md5: commande introuvable
decode_to_md5: command not found
decode_to_md5: käsku ei ole
decode_to_md5: không tìm thấy lệnh
decode_to_md5: komanda nerasta
decode_to_md5: Kommando nicht gefunden.
decode_to_md5: kommandot finns inte
decode_to_md5: komut yok
decode_to_md5: nie znaleziono polecenia
decode_to_md5: níor aimsíodh an t-ordú
decode_to_md5: no se encontró la orden
decode_to_md5: no s'ha trobat l'ordre
decode_to_md5: opdracht niet gevonden
decode_to_md5: parancs nem található
decode_to_md5: perintah tidak ditemukan
decode_to_md5: príkaz nenájdený
decode_to_md5: příkaz nenalezen
decode_to_md5: команда не найдена
decode_to_md5: командата не е открита
decode_to_md5: 命令找不到
decode_to_md5: コマンドが見つかりません