Ticket TimeStamp problem


For some reason my RT is sending the emails when any action is configured
with 4 hours of difference from the real time.

from GUI:
Dates https://srthr31/Ticket/ModifyDates.html?id=1934 Created: Wed Jun 02
14:10:24 2010
from email sent:
Created On: 2010-06-02 18:10:24

In MySQL - the ticket information have this same time. I checked MySQL
server variable :
time_zone SYSTEM

Ubuntu Server configuration:
Current default time zone: 'America/Puerto_Rico’
Local time is now: Wed Jun 2 15:23:01 AST 2010.
Universal Time is now: Wed Jun 2 19:23:01 UTC 2010.

Any configuration should I need to look at? Can someone point me to where