Lots of PHP error messages

You need to change your PHP preferences in the php.ini file.

See:
https://www.open-emr.org/wiki/index.php/FAQ#What_are_the_correct_PHP_settings_.28can_be_found_in_the_php.ini_file.29.3F

You need to change error reporting to:
error_reporting = E_ALL & ~E_NOTICE & ~E_STRICT & ~E_DEPRECATED

The symbol “~” means “NOT”. So, the above line means Notices and deprecated messages will not be displayed.