Folder created out of its group

[mytskine]

• I login as admin (uid=1) and go to the folder page of an empty private group: /oa/kb
• I create a folder though the web interface: /oa/kb/node/add/folder
• When I click on save, I am redirected to /oa/kb/node/225 BUT every folder of every group appears on this page. The hierarchy is different each time: sometimes the group I just created seems to have children, sometimes not. Some root folders are listed as sub-folders of folders from different groups.
• When I go back to the folder page of this group /oa/kb, it is still empty. The folder I created is not visible.

I checked this with another account that has administrator rights.
I also checked the permissions were all granted for book* and folder* (though as admin it shouldn't be a problem).

OA 1.2 installed in a virtualized server (Debian amd64, apache2), not in the root of the virtual server but in /oa/.

[mytskine]

I explored the database of the buggy instance, and discovered that each "sane" folder has a record in the table "book" with its "nid" and a record in "menu_links" with its "node_path". Folders that are not displayed in their groups lack these records. I'll try to find why these aren't created sometimes.