I have a car club website that uses zenPHOTO to display photos from different outings. I'm trying to make a custom link to the club home page from the zenPhoto using the Menu Manager. When ever I hit apply I get the "Cross site request forgery blocked" I am using the collections theme

That's a known bug that is already fixed in 1.6.1a:
https://github.com/zenphoto/zenphoto/issues/1367

1.6.1a is not really for production use yet. You could try using the menu_manager plugin only from it but I cannot promise that it will work with 1.6 right away. There might be some incompatibe changes under the surface.