During the PHP Live! installation, a configuration file will be automatically created at the following location: phplive/web/config.php

The phplive/web/config.php file contains various values, including the directory path information and the MySQL DB values.  Before anything, backup the config.php file just in case you need to revert back to original.  Once a backup has been made, edit the file and you'll see values similar to:

$CONF['DOCUMENT_ROOT'] = addslashes( '/path/to/your/phplive/system/phplive' ) ;
$CONF['BASE_URL'] = 'http://www.yourdomain.com/phplive' ;
$CONF['SQLHOST'] = 'db_host' ;
$CONF['SQLLOGIN'] = 'db_login' ;
$CONF['SQLPASS'] = 'db_password' ;
$CONF['DATABASE'] = 'db_name' ;

Update the values for the changed directory path, changed PHP Live! URL or changed MySQL information.  All other configuration values SHOULD NOT be modified or your PHP Live! system may not function properly.