rt-setup-database: 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/sbin/rt-setup-database - from package: rt3

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

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