bf_compact: 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/bf_compact - from package: bogofilter

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

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