To fix the error messages you're getting in your fail2ban.lo you need to upgrade your python version to 2.5
follow the steps below.
2009-06-19 21:07:28,487 fail2ban.server : ERROR Unexpected communication error
It's related to the python version, some type o incompatibility with ubuntu 9.04, this is what you had to do to fix this error:
1. Install python2.5 ( sudo aptitude install python2.5 )
2. edit file /usr/bin/fail2ban-server , change the very first line "#!/usr/bin/python" to "#/usr/bin/python2.5"
3. restart fail2ban
Go click on the link below, it will help you setup fail2ban for your ftp server as well.