Description:
------------
Once again trying to get Drupal to run with PHP 6.

I'm getting the following error on the first query that is run..

Fatal error: Uncaught exception 'PDOException' with message 'SQLSTATE[HY093]: Invalid parameter number: parameter was not defined' in .../drupal7/includes/database/database.inc:1941

That line looks like this:
<?php
    $return = parent::execute($args);
?>
Note: parent is PDOStatement.

The executed query:
unicode(87) "SELECT data, created, headers, expire, serialized FROM cache_bootstrap WHERE cid = :cid"

$args contains:
array(1) {
  [u":cid"]=>
  unicode(9) "variables"
}

I would suspect that it does have something to do with unicode.