According to what I can find concerning that error and the fact this is on a shared host, am wondering if the instance is pointed to a php version that supports 2.5. Remotely hosted systems might be running multiple versions of PHP and one has to point the higher version. Reason am thinking that ... /usr/lib/php5. That php5 might be a version 5.2 and not the required 5.3.x+
Please see:
http://www.inmotionhosting.com/support/edu/moodle/errors-unicode-database-undefined-constant
Create a phpinfo page and drop it in the root of the new install. Call the page info.php and it's contents look like:
Then hit the site with browser pointing directly at the info.php file: http://yoursite/yoursubdirectories/info.php
How to point to the required PHP is a question to ask your provider.
'spirit of sharing', Ken