After Login: 'Warning: Cannot modify header information - header already sent' and 'Strict Standards message'

[Felix-MFU]

I am getting this results after clicking on log in in and being sent back via the Facebook page to login.php:
(Note: I am running this as a test user)

Strict Standards: DateTime::__construct(): It is not safe to rely on the system's timezone settings. You are required to use the date.timezone setting or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier. We selected 'Europe/Berlin' for 'CEST/2.0/DST' instead in /homepages/38/d149170612/htdocs/nowhereandnever/Facebook/Authentication/AccessToken.php on line 156

Warning: Cannot modify header information - headers already sent by (output started at /homepages/38/d149170612/htdocs/nowhereandnever/Facebook/Authentication/AccessToken.php:156) in /homepages/38/d149170612/htdocs/nowhereandnever/login.php on line 25