CentOS

Hi, I wanted to know if they could help me solve the following drawback.

Service proftpd start:
PROFTPD FAILD

Log:
Checking syntax of configuration file
- using TCP receive buffer size of 87380 bytes
- using TCP send buffer size of 16384 bytes
- mod_tls/2.2.1: using OpenSSL 0.9.8e-fips-rhel5 01 Jul 2008
- <IfModule>: skipping 'mod_ban.c' section at line 156
- warning: unable to determine IP address of '204-45-252-122.firehosted.com'
- error: no valid servers configured
- Fatal: error processing configuration file '/etc/proftpd.conf'

/etc/host
# Do not remove the following line, or various programs
# that require network functionality will fail.
127.0.0.1 localhost.localdomain localhost
::1 localhost6.localdomain6 localhost6


Thanks for your attention

It's trying to reverse lookup what it thinks is your hostname "204-45-252-122.firehosted.com" and failing. You either need to fix your DNS or add that to your hosts file or amend the proftpd config so it doesn't try to use that hostname (no idea how!).

Trevorh thank for comment. Anyone a solution ? thanks

TrevorH gave you the solution.
Fix your DNS or fix your hosts file so that it has your machines IP address associated with your FQDN.

Sorry for my ignorance, as Should do to solve it? instructions

If you are going to run unsupported software on CentOS you need to have a basic proficiency with Linux.
CentOS ships vsftpd not proftpd. Why are you not running vsftpd?