Actually, i have no idea. I assume it is correct because I'm also running a phpBB forum(on the same server) with a tons of members for a WoW Guild and do _NOT_ have any problems at all with register dates.
Just for reference as well.. this is not locally hosted. It's hosted on http://bluehost.com -- I did email them after recently having this problem and their in Mountain Standard Time(-7).
I have noticed though that when users register they seem to not change their own time zone setting (most of the users are EST(-5), could that be the problem?
And lastly, while registering test users to see if i could reproduce the errors.. I think I may have found a bug.
While either logged out, or logged in as a regular user (not admin), my register dates display correctly.
But if I log in as Admin it gets screwy.
Example. I created a test board yesterday, so obviously the register date for my admin account would state "yesterday".. but if I'm logged in as Admin it says I registered "Today".
When I log out and go to view the user list page, it says I registered on the correct date ("Yesterday")
And more further testing reveals.. that even while logged in on the test user i just created.. changing the Time Zone setting from -7 MST, to -5 EST makes the admin user screwy again. Instead of it displaying correctly while logged in non-admin, it now displays the admin registed "today", which is obviously not true. Because I registered that account last night.. which is technically "yesterday".
Hope this helps at all. And I hope you can fix the error.
Just for good measure though, how can I go about seeing if my server time is set correct?