Thread:Project:Support desk/blank start page after new installation and configuration/reply (3)

Only the first warning is related to the timezone thing. This shouldn't cause any badness other then an ugly warning message (The ugly warning should not be displayed, its a bug from when MediaWiki is used with php 5.4 or greater. It should be fixed next version. The previous comments in this bug give work arounds. An even easier work around is putting something like  at the bottom of LocalSettings.php. See manual:$wgLocaltimezone for details on what that does)

The other warnings are due to whitespace in the beginning of your LocalSettings.php file. Make sure that there are no newlines (or anything else) between the start of that file and. If it looks like there's nothing there, you may also have to check for BOM's, but the error message said line 3, so unlikely to be a BOM

In this case, the no output might be an issue with redirection (since http://www.menschen-gerechte-gesellschaft.de/wiki/index.php/Hauptseite works fine). I suspect the warnings being output (headers already sent) prevent MediaWiki from being able to do redirection. I think once they are all cleared up, your site will probably work fine (Well it also looks like you need to run update.php/ the web upgrader to fix the survey extension).