Unable to select taxonomy items when creating new content

I have taxonomy items with multiple hierarchy:
First I've created level one items:
-item1
-item2
-item3
...
-item12
and then added sub1 - sub12 items and make all items above their parent items, so item1 has sub1, sub2,...sub12; similar item2 has sub1, sub2,...sub12 etc...
--sub1
--sub2
...
--sub12
When creating such hierarchy using admin menu it gets created OK and I can see all sub items under each item1, item2, etc...

However when trying to create a new page I'm able to see and select only some sub-items for a few first level1 items. No sub items are displayed for item11 and item12 and some other items missing their sub items as well.

I'm using Drupal 4.7.6 on PHP5.2.0 (in CGI mode). PHP memory limit is 64M.
Modules used: basicevent, blog, book, captcha, comment, contact, event, i18, locale, tagadelic, taxonomy, taxonomy_breadcrumb, translation,throttle, upload, tracker.