Error … while accessing word press blog on my site

I have wordpress installed at subdomain of my site name http://stuff.infoact.net
Though i have created database and uploaded my previous bakcup (Which i took from my last server) to new database of mysql.

in wp-config it was “infoact_wp and password” previously
In new server I create “infoactn_infoactwpdb and password”

Though i have changed database info in wp-config.php with new database name & proper password, Still it says..

Warning: Cannot modify header information – headers already sent by (output started at http://infoact.net/includes/top.php:8) in /home/infoactn/public_html/stuff/wp-includes/wp-db.php on line 304

please help