Error in CWP7 after install

I have this Error after install my CWP7

how can i solve this error pls help!:

Warning: mysqli_connect(): (HY000/1049): Unknown database 'root' in /usr/local/cwpsrv/htdocs/resources/admin/include/functions.php on line 0

Warning: mysqli_connect(): (HY000/1049): Unknown database 'root' in /usr/local/cwpsrv/htdocs/admin/admin/index.php on line 0

it was not clean installation!
The best way is to install on brend new Centos 7! you can workaround but,  for lather use is not good!