Can't edit permissions Drupal 7.21
For some reason I can't edit/add permissions for certain content to ANY roles anymore.
I first noticed this with one role and that had certain permissions missing.
Added the missing permissions and tried to save, but it always reverted back to before save.
I deleted the entire role and  it doesn't take any permission. 
Other roles the same issue, can't add any additional permissions for create content even for r administrator (User1)
I experienced this under Drupal 6.x - it is possibly a similar experience on Drupal 7.x.

The Apache error log (/var/log/httpd/error_log or similar) may show something similar to the following:

... [error] [client ... ] PHP Warning:  Unknown: Input variables exceeded 1000. 
    To increase the limit change max_input_vars in php.ini. in Unknown 
    on line 0, referer: https://.../admin/user/permissions


To resolve add the following to php.ini

max_input_vars = 2000


Reload Apache per your operating system and increase setting if pain persists.