I've just installed 1.6 RC3 on my iMac, and things are working nicely on the whole. This is my first experience with osTicket.
I do notice that there is a warning message in my php error log:
PHP Warning: require_once(./main.inc.php) function.require-once: failed to open stream: No such file or directory in /filepath_to_osticket/scp/staff.inc.php on line 20
I inserted an echo statement and noticed that ROOT_PATH.'main.inc.php' is not resulting in "../main.inc.php", instead it is "./main.inc.php".
I'm not in the mood to delve into this mystery further, so I just changed ROOT_PATH.'main.inc.php' to '../main.inc.php' . No more warning!