wp-admin does not redirect to dashboard

I have a weird problem, which I could not solve yet. I installed wordpress 3.4.1 and made an own template. I use one plugin – qTranslate. Everything is fine on my local copy and also on my dev copy dev.mysite.cz.

When I copied wordpress and log in on the main site, http://www.mysite.cz, the dashboard does not show up. Instead I only get the homesite with the administration panel on top of the page.

The only difference I can so far tell is in the wp-config.php file. In production mode I have this two more directives in it:

/** debugging mode */
define('WP_DEBUG', false);

/** Localisation */
define('WPLANG', 'cs_CZ');

Any advice will be very appriciated.
Thanks

The problem was in .htaccess. There was an old global .htaccess file (from the old website) besides the wordpress one which was hidden on the sever (by admins of the hosting company) which rewrite rules harmed the ones in wordpress. I actually had to contact the admins and ask them to remove those rewrite rules.