Hi,
I have 2 problems with my k2 installation
(Joomla version 2.5.6 Stable, K2 version v2.5.7 )
remontiram.com

1 Installed Bulgarian language
Still not recognized on some places where k2 filtrify module is used

2. Adding New item after registration gives me 403 permission error .
(the link name for adding new item is "Нова статия" and is available after log-in)

:dry:
10x in advance

Hi. Regarding your questions:

1. Each module has it's own language files, so since you use a third-party module you need to find the Bulgarian language file of it ( Or translate it by yourself ).

2. Check again your permissions in K2 user groups. Ensure that the user can also publish the item.