Error 404 (A server error occurred while loading the tabs)

[Blanka]

I am using Prestashop 1.6.1.0.

 

I deleted my old prestashop & theme and installed a new version. But now I have big problems and I am very very desperate :(

 

I can`t add new product without EROR 404! Everytime I add a picture or anything else in to product or add a product or vatever I do; my site "breakes down" and end in 404 eror. Sometimes I recive a messagees :

 

Tab : Features (404)
A server error occurred while loading the tabs: some tabs could not be loaded.
Please try again by refreshing the page.
If you are still encountering this problem, please check your server logs or contact your hosting provider for assistance.

 

Tab : Prices (404)
A server error occurred while loading the tabs: some tabs could not be loaded.
Please try again by refreshing the page.
If you are still encountering this problem, please check your server logs or contact your hosting provider for assistance.

 

and the same for suppliers...

 

The same problem with error and ending a page is in my out public store. When someone select an article or category, the site "breakes down" to eror 404.

 

I need like a 10 minutes for all refrashing and erors to add one product

And the site acting reaaaaaaly slowly. For one click to open something need about 15 seconds?! My internet is ok. This problem is just on my site.

 

 

What can I do. Please help me, I don`t know how to fight with this bug

 

Thaaaaaaaaaank you!

And sorry for my poor english.

Edited October 10, 2015 by Blanka (see edit history)

[NemoPS]

Sounds like a server issue. Anyway, turn on dev mode as described in my signature and see if those 404 display something else. Also, check the server error logs, it might be due to random permission errors with mod_sec or alike