mtbl_info: 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/mtbl_info - from package: mtbl-bin

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

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