After upgrading NextGen to the latest version I got this error message when I did a search on my site (I use Relevanssi plugin):
/var/www/qb401131/data/devoedzamekeuken.nl/irisindekeuken/wp-content/plugins/nextgen-gallery/products/photocrati_nextgen/modules/nextgen_basic_singlepic/templates/nextgen_basic_singlepic.php is not a valid MVC template