flatbat: 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/flatbat - from package: munipack

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

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