Hemos encontrado un bug en el plugin next gallery que impide visualizar los efectos javascript.

La solución es esta:

Desde el panel de administración:

"Gallery" --> "other options" --> "lightbox effects" --> "(Show advanced settings)"

En Stylesheet:

http://.blogs.uv.es/wp-content/plugins/nextgen-gallery/products/photocrati_nextgen/modules/lightbox/static/fancybox/jquery.fancybox-1.3.4.css

En el javascript cambiar las lineas por: 

http:/.blogs.uv.es/wp-content/plugins/nextgen-gallery/products/photocrati_nextgen/modules/lightbox/static/fancybox/jquery.easing-1.3.pack.js

http://.blogs.uv.es/wp-content/plugins/nextgen-gallery/products/photocrati_nextgen/modules/lightbox/static/fancybox/jquery.fancybox-1.3.4.pack.js


http://.blogs.uv.es/wp-content/plugins/nextgen-gallery/products/photocrati_nextgen/modules/lightbox/static/fancybox/nextgen_fancybox_init.js
 Pulsar Guardar y listo.