Linux Piwik Installation Issue

Hello Piwik community.

I was trying to install the latest version of Piwik available on my Linux web server and I encountered two problems.

First of all, after the system check, I had a warning telling me that I had to modify my php.ini file by enabling always_populate_raw_post_data = -1. After doing so and restarting Apache and rebooting the system the following error showed up when Piwik began with the system check: Piwik encoutered an error: Maximum execution time of 30 seconds exceeded (which lead to: SQLSTATE[28000] [1045] Access denied for user ‘www-data’@‘localhost’ (using password: NO))

Second, after commenting again always_populate_raw_post_data = -1, the error mentioned before remained right before performing the system check.

What does the error mean, and is there a way to fix it?

I would appreciate any help tremendously.