Hello,
I have a huge problem with this quest and I hope you can help me.

First of all, I'm playing the German PS3 GOTY edition, the language is switched to English. Maybe this is relevant.
The bug occurs during the quest "Rebuilding the Gatekeeper" where you have to collect the 4 ingredients in the Gardens of Flesh and Bone. The problem is that I can't pick up the Osseous Marrow because a part of the tree is missing. That means the little lantern is just floating in the air and there is no Osseous Marrow. The tree doesn't look like this, the upper part is missing: http://www.uesp.net/wiki/File:SI-object-Osseous_Marrow.jpg

I already tried to load a savegame from before entering the cave but that didn't solve the problem, neither did waiting in front of the tree nor transporting the savegame to a new user on the PS3-system.

Did anyone of you experience this glitch? It would be a real shame if there was nothing that could be done about this because I have already invested more than 180 hours into this savegame.
Thanks in advance!