1.6.5RC? There never was a 1.6.5RC release. There were multiple 1.6RCs, and a 1.6ST. After that it jumped to 1.7. If you cannot upgrade you would simple want to move the code from the original installation into the new folder on the new server. And then export the database (.sql) and import it into the new MySQL instance on the new server. If you changed the name/ip of the machine you would want to check your /include/ost-config.php (note that in 1.6 it might be called settings.php or ostconfig.php and may be in the root folder) and check what you have for the address of your DBHOST. You also of course need to make sure that your MySQL user and password are right and have access to the "new" database (check the privs).If you are still getting a white page then changes are there is an error being thrown... You can enable error displaying in php or by following the wiki:Self-Help Troubleshooting
If you can not find any solutions to the problem you are having, you can enable the "Show Errors" flags located in /main.inc.php:
#Don't display errors
ini_set('display_errors',0);
ini_set('display_startup_errors',0);
Change this to:
ini_set('display_errors',1);
ini_set('display_startup_errors',1);
Then errors should be displayed either in your web browser or in your server's error.log file.
Moreover, don't forget to check your osTicket Dashboard page and your mail server log.
source: http://osticket.com/wiki/Installation#Self-Help_Troubleshooting