After install, cant sign in into home page or admin page

[root@test1 var]# php -v

PHP 5.3.27 (cli) (built: Aug 22 2013 18:06:38)

Copyright (c) 1997-2013 The PHP Group

Zend Engine v2.3.0, Copyright (c) 1998-2013 Zend Technologies

my php version

after install cs-cart ultimate 4.0.1

going into admin page, enter username and password, submit, and go back to same page

same with sign in into the homepage

whats the problem?

i start clean install with demo product

I just try to register guest, just go back to same page. cant sign in the new guest, no error information at all. site working perfect with demo page.

let me check into phpmyadmin to check if the guest i just register

update: i just check into pma, there is admin, and user i just register.

but i cant sign in at all (no notice of error),

when i register, no message, your user succesfully register… nothing but back into same page.

i try to clear cache which i did by delete var/cache

same thing

clear your browser cookies for that domain.

Same result even in new browser