Hello to all the forum I have a problem with k2 on joomla 2.5, I do not understand why and I do not understand how to solve certain categories display some pages completely white all gone
I'm looking for help to solve this problem

You need to enable error reporting from your Global Configuration tab to see the actual error.

I do not understand why in some categories do not have errors and other mistakes you've enabled system joomla but I did not write any

It is possible that a content is running which produces these errors.
Finally to enable error reporting your configuration.php file should be writable.