After checking "Log events to
qa_eventlog database table" and clicking "Save" the page is blank and URL is not changing.
I checked my server error logs:
[11-May-2012 09:57:48] PHP Fatal error: require() [<a href='function.require'>function.require</a>]: Failed opening required '/webseiten/gute-mathe-fragen/qa-include/qa-install.php' (include_path='.:/usr/local/lib/php') in /webseiten/gute-mathe-fragen/qa-include/qa-index.php on line 146
So the qa-install.php was missing.
Copying it to the server fixes the problem.
-> Cannot remember to have deleted this file. Can somebody confirm that it has to be there even after installation of q2a core?