ufobuilder: 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/lib64/parrot/3.3.0/languages/perl6/bin/ufobuilder - from package: rakudo-star

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

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