error 404 (not found) in product page

Hi!
I have a problem with the marketpress plugin.
I have installed wp multisite with subdomains and installed marketpress, all looks well, but when you open a page of a product or a category I get a 404 error.
I tried disabling all plugins and widgets, change the template but the error is the same.
I read this: https://premium.wpmudev.org/forums/topic/marketpress-product-page-404 (but the problem was a plugin, and I disabled all)
You can check it here:
http://pruebita.ecommerce.uy/tienda/productos/categoria/ejemplo/ (category with 404)
I can search for a product (and the product is there) http://pruebita.ecommerce.uy/?s=productito
But if i click in the product i get a 404 error again
http://pruebita.ecommerce.uy/tienda/productos/un-productito/
Any suggestion?
Thank you!