Problem with synchronization/copying parent categories between WordPress’s blogs

LINK TO PROBLEM WITH SCREENSHOT:
http://bart.czechowice.net.pl/png/wppost.pdf

Hi! This is my first post but I really need your help.

I’m working with “Wordpress 2.5.1” and “Ruby on Rails” on “Windows XP”

Problem description:

I have two WordPress’s blogs, first blog is ‘Master’ and second is ‘Slave’.

Master – source blog
Slave – destination blog

In my application in Rails I am trying to copy categories with relationships between posts from ‘Master’ to ‘Slave’. Everything is OK for categories which don’t have parent categories but I have strange problem for taxonomies with parents.

Details:

Category WITHOUT parent and CORRECT results(copied “Without Parent” from ‘Master’ to ‘Slave’) on both blogs:

http://bart.czechowice.net.pl/png/one_cat_correct.png

Category WITH parent and my “strange”problem:
I have three categories:
‘Home’ which belongs to ‘Work’
‘Work’ which belongs to ‘Main’
I chose one post which belongs to ‘Home’ category to synchronize it. My categories (Main::Work::Home) should be displayed in ‘Slave’ as the same tree in ‘Master’ but they are not.
It looks like:

http://bart.czechowice.net.pl/png/parent_cat_incorrect.png

After synchronization I checked what happened in database in MySQL GUI and also checked how it looks in WordPress’s admin panel.
My post from ‘Master’ was copied to ‘Slave’ and is displayed on “Post List”:

http://bart.czechowice.net.pl/png/slave_post.png

Screenshot from MySQL GUI (‘Slave’):

http://bart.czechowice.net.pl/png/mysql_gui.png

Admin panel (‘Slave’):
When I am writing a post in ‘Slave’ I can see that categories here..

http://bart.czechowice.net.pl/png/slave_writing_post.png

but when I switch to ‘Manage->Categories’ I have something like this:

http://bart.czechowice.net.pl/png/slave_manage.png

but it should looks like:

http://bart.czechowice.net.pl/png/slave_manage_correct.png

THE STRANGE THING:
I opened the panel with categories and edited ‘Uncategorized’ category. AFTER that WordPress engine made some changes and my categories were correctly displayed:

http://bart.czechowice.net.pl/png/slave_tree_correct.png

This is only an example, because when I added new post to ‘Slave’, categories were also correctly displayed. Any changes which WordPress do can repair my problem but I haven’t seen any changes in database in MySQL GUI so what is wrong ?
Summarazing, my main question is:
What extra operations WordPress does, when it is writing anything to database ? Guess, I have to do the same operations to repair my application.

Any help or advices please 🙂