I am using the latest version of WordPress and NextGen Gallery.
I have a little different setup than a regular WP setup. All my core WordPress files are symlinked from a different directory into a site's document root and all the plugins are local to the site.
Here is how it is setup
/var/DOCROOT/wp-admin -> symlink to /var/DIR/wp-admin
/var/DOCROOT/wp-include -> symlink to /var/DIR/wp-include
/var/DOCROOT/wp-content -> local to the site
/var/DOCROOT/wp-content/plugins -> local to the site
When I install the nextgen gallery and activate I can view the Overview page. However, when I go to Add Gallery/Images page I get the following error:
/var/DIR/DOCROOT/wp-content/plugins/nextgen-gallery/products/photocrati_nextgen/modules/nextgen_addgallery_page/templates/upload_images.php is not a valid MVC template
All other plugins work absolutely fine.