Thread:Talk:Semantic Bundle/Class 'ValueValidators\NullValidator' not found

I just tested the new Semantic Bundle (1.9.2) on MW v1.21.2 (PHP 5.3.27 (cgi-fcgi) + MySQL 5.1.69). Upgrading and initialising tables were successful, but attempting to open a page yields the following error message instead:

Fatal error: Class 'ValueValidators\NullValidator' not found in [...]/extensions/SemanticBundle/param-processor/param-processor/src/ParamProcessor/ParamDefinitionFactory.php on line 150

which refers to the second line of  if ( $validator !== '\ValueValidators\NullValidator' ) { $definition->setValueValidator( new $validator ); }

Perhaps bug 56663 is related to this issue: https://bugzilla.wikimedia.org/show_bug.cgi?id=56663