using the assistant for using the thunderbird address book leads to wrong data in the birthday year (here appears the month) the birthday month (here appears the day) and the birthday day (always empty) (no problem in OpenOffice 2.4.2)
I can confirm it in LibO 3.4.4. This happens in OOo 3.4Beta, OOo 3.3, 3.2.1, and OOo 3.2 where I have tested.
*** This bug has been marked as a duplicate of bug 44065 ***