Hi,
I hope someone could help me find out what is the matter with my saved game...

I have Oblivion GOTY edition for PS3. I made the system update today, just to be sure, but it did not help.
The problematic quest's name is Addiction, in the Shivering Isle. I can find the felldew to enter - no problem there. But as I proceed in the dungeon and trying to save my game, sometimes the controller goes numb, and the game is stuck in the options screen, before loading the saved slots, and the only thing I can do is to switch off and on the PS3, and start all over from the previous save.
My first attempt was to finish the dungeon without saving, but the game stops before the loading screen, when I try to go outside the final door in the Dunroot borrows, sanctum of decadence. I also hoped (my second attempt), that after getting the chalice of reversal, i can go back all the way to the entry, and walk out that door, but the same happens as with the final door, no loading screen, game stops completely.
I've found out that if this saving issue occurs in the dungeon, the game _will_ crash at the exit or entry door, so i started to save _very_ frequently (after sneaking past each monster etc.) to see if there is a certain physical point in the dungeon, where "bad things" happen, but couldn't find any.
I've tried to find out what action is triggering this saving problem, but every "algorythm" I was trying failed at a certain point. The best result was that I sneaked past enemies without killing them, did not harvest anything, did not loot any container, so I managed to reach the third level in the dungeon (Dunroot burrow, drone tunnels), but that's all. I still think that the triggering effect is when an eltyra with random loot (can be a fork or lockpick or flawless sapphire) dies somewhere in the dungeon, but its not for sure.
As you probably know, if i can't finish this quest, I can't proceed in the the main quest of the shivering isle, and it would be very frustrating after a few hundred hours of game time, at level 38

I also tried to load a previous save, because maybe this file is corrupted, but it couldn't help either. Maybe the save is not old enough, one (real-time) hour older... what do you think?

Any ideas what to do?
Thanks in advance...