ftp service offline

Hi all,
I've installed ISPConfig by this manual http://www.howtoforge.com/perfect-server-centos-5.3-x86_64-ispconfig-2
and now i receive every 30mins a message from ispconfig with text "WARNING: service ftp not running (server: hosting.mydomain.ru, port: 20)!", althrough ftp-server actually works fine and WEBUI in "Status" tab shows it as online. Proftpd listens 127.0.0.1 and 2 other real IP.
/var/log/messages - indicates clean start/restart if i restart it:

Code:

Sep  1 11:45:21 hosting proftpd[24774]: localhost.localdomain - ProFTPD killed (signal 15) 
Sep  1 11:45:21 hosting proftpd[24774]: localhost.localdomain - ProFTPD 1.3.2 standalone mode SHUTDOWN 
Sep  1 11:45:22 hosting proftpd[25092]: localhost.localdomain - ProFTPD 1.3.2 (stable) (built Tue Aug 25 13:53:29 YEKST 2009) standalone mode STARTUP 

moreover, i cant find any errors in logs at all, but still gets this annoying emails...
Please tell me what's wrong

 

Code:

[root@hosting tmp]# netstat -tap | grep ftp
tcp        0      0 *:ftp                       *:*                         LISTEN      6159/proftpd: (acce 

 

I have it:

Code:

127.0.0.1		localhost.localdomain localhost

 

Port 20? FTP uses port 21.

 

Well, 21 port for controls, 20 port for data (active) or random high (passive)
But it's not the point, as "port 20" only in system emails from ISPConfig, apperantly i dont have any relation to their content. That is the problem - ftp server works fine, but ISPConfig thinks its not :/