I've had the same problem when trying to install Moodle 2.3.1 (both the standard and latest stable versions); I'm getting the following error:
Notice: Use of undefined constant __DIR__ - assumed '__DIR__' in /home4/cjritter/public_html/2012-13/moodle/lib/dml/moodle_database.php on line 27
Warning: require_once(__DIR__/database_column_info.php) [function.require-once]: failed to open stream: No such file or directory in /home4/cjritter/public_html/2012-13/moodle/lib/dml/moodle_database.php on line 27
Fatal error: require_once() [function.require]: Failed opening required '__DIR__/database_column_info.php' (include_path='.:/usr/php/54/usr/lib64:/usr/php/54/usr/share/pear') in /home4/cjritter/public_html/2012-13/moodle/lib/dml/moodle_database.php on line 27
I've followed the previous post's suggestion to select the right version of PHP in my web host's PHP Config app. Switching between PHP 5.2, 5.3, and 5.4 didn't affect the error.
I did notice that when PHP 5.3 is selected, my host reports its version as 5.3.14, and Moodle wants 5.3.2. Does Moodle not like PHP 5.4.5 either?
Here's some additional info that might help:
| Apache version | 2.2.22 |
| PHP version | 5.4.5 |
| MySQL version | 5.1.63-community-log |
| Architecture | x86_64 |
| Operating system | linux |