I installed the last 18.104.22.168 and it really works with no problems.
the problem is, that mine installed PHPBB2 forums are heavily modified versions, with some custom add-ons, and I cannot simply overwrite all of them.
On the other side, PHP 5.0.2 is much more stable on Win platform, so I won't degrade.
Is there anyone, who would know which part of code was problem for "moderator privileges" bug, so I could edit it manually.
How to set moderator privileges manually direct into database?