URL in Pages 4.0 (index page)

[Bazilisk]

Have problem with URL links in Page's CMS.
Link http://bullion.ru/cat/index.html work Ok, but when I try to access http://bullion.ru/cat/ I get error

Is it possible to fix it?

[opentype]

What are you URL slug settings for the page / database / category?

It looks like you have manually used “index.html” as URL slug, which you don’t need to do. 

[Bazilisk]

Yeesssssssssss!

Thank you Ralf!!!!!!!!!!

[Bazilisk]

Ups, new problems

The page name automatically changed to pages Title. Its impossible to save Filename clearly

[Bazilisk]

Ups 2.

This error just for very old pages