Per email feedback:

I have tried to install piwik for many hours.
I have read your manual and forums several times.
I had many messages about missing database, settings etc.
My solution was found on http://stackoverflow.com.

I would recommend you to put the php.ini setting "max_execution_time = 0" in red at the beginning of your installation manual.
This will help many noobs like me for sure. :-)

-> We could add a new diagnostic that checks that max_execution_time is set at least to 30 or to 0 (unlimited).