Galleries won't show up

Hello,
I have a problem with my photography wp site: the galleries won’t show up.
I’ve created 4 galleries, all of them with a set of photos, in 3 different categories. Yet whenever I try to open a gallery page (clicking on Gallery Category — Name of the gallery — View), I get a page with an error message: “Error 404, page, post or resource can not be found”.
I’m running the premium template Tripod.
This is one of the galleries page: http://takuma-ikeda.com/gallery/nature/
You can find the other galleries on the main page: http://takuma-ikeda.com/
If you click on the main directory “Galleries” you can see only one set (which is also a bug, since I’ve selected “show all categories”).
Could someone help me please?
I really can’t run my site without the pictures.
Thank you in advance!