why I can't log in my control panel ?
when I tried to log in, it goes to http://192.155.81.136:7778/htmllib/phplib/

We don't know what operating system you are running.
We don't know what web server you are running.
We don't know what web applications you are running.
We don't know what control panel you are running.
We don't know what URL you are trying to visit.
We don't know what error messages you are seeing.

Without information about your situation, it's difficult for anyone to help.

CentOS 5.6
3.zencart
4.Kloxo
5.www.sportmaglie.com/
6.when log in the kloxo control panel, it shows 500 internal Server Error

There's 4000+ hits when you Google "kloxo control panel 500 internal Server Error" - do any apply to your setup?

When I go to: http://192.155.81.136:7778/login/ it goes to a Kloxo login screen.

_________________
Either provide enough details for people to help, or sit back and listen to the crickets chirp.
Security thru obscurity is a myth - and really really annoying.