Date and Time

On OS X server (10.2.5), I cannot choose a time zone inside the United States. I can pick a time zone anywhere in the world except here in the US. When I try and synch my server up with a time server, I get a different time because I cannot get the correct time zone. As a fix, I had to choose Bogata Columbia time zone (equivalent to EST). Is this a bug or am I missing something.