Question: What should be technically considered for smooth HCnix installation before running HCnix installer on the server?

Answer: Following considerations should be kept in mind before HCnix installation :

1.  Only for CentOS: upgrade PHP 5.1.x to 5.2.x , with the help of this kb http://portal.hostingcontroller.com/KB/a152/hcnix-throwing-exception-while-create-new-domain.aspx
2. Install /configure MySQL and give enough permission  to it by using this command from MySQL shell.

Grant all privileges on *.* to root@ServerIP identified by 'root-password' with grant option;
              Flush Privileges;

You may have to configure my.cnf and set the bind-address to the IP on which MySQL server will listen.

             Now run the HCnix installer and the installation shall go smoothly, in case of any issue feel free to contact HC support