Your FTP appears to run and listening for connections. That's good.
What about checking your logs for errors? Run something like that and check for possible causes:
# cat /var/log/messages|grep proftpd|less
I assume that by saying "it is not working" you mean that the username/password combination appears invalid (so you cannot login at all). Check in the logs using the above command for what exactly proftpd is complaining about, and we 'll see.