set_userdata() not work

[eluser]Pakm@n[/eluser]
[quote author="InsiteFX" date="1338178924"]If the timezones are not correct the time for sessions and cookies will not match and cause problems!

If the server is in Mexico then just set the timezone like I showed you above to Mexico.
[/quote]
Actually the default time zone was set on the user controller, and i set it to the login controller and the index.php, but still didn't work.
It's really weird, i will ask my client if it works well down there, if it is i think i souldn't worry about it, but still it kinda worries me a little bit.

I made some tests and it actually goes to the validate credentials and passes the first condition (the username and pass are correct) but it doesn't set the is_logged_in = true on the cookie :-S

You have any other ideas why it isn't working?

Thanks for your help