Site Hacking attempts

Hi,
I had my site hacked under an earlier version of an install. Since than I upgraded to version 1.0.2. I cleaned everything completely out. I keep having attempts to connecting to my system through this file: /manager/includes/extenders/dbapi.mysqli.class.inc.php .

I also see this in my error report:

$this->conn = new mysqli($host, $uid, $pwd, $dbase);

DBAPI->connect()
manager/includes/document.parser.class.inc.php on line 2003

The request URI and referrer do not exist on my hosting either. I deleted them.

Could this file above cause me issues on being hacked again on my system. It keeps saying:
Error : mysqli::mysqli(): (42000/1203): User ******* already has more than 'max_user_connections' active connections.

Any help would be appreciated, thank you.