I have finaly goten up to where Cet casts Twisted Master on Kerah at the 2nd portal of Isis.... but soon after (like 15 secs) the games frezes.. in fact the whole computer does.... and it is realy shitin me off to come this far, just to get this bug!..... i have heaps of Hoyl water to use... both champion keys.... and am aching to finish the game.
If anyone has encounted this bug, or has any ideas how to fix it PLEASE help me out here!

I'm stuck here too! Keep reloading and going throught the whole Portal/Cet/Kerah scene again and again. But as soon as I do anything apart from moving, like spells or fighting, the d@mn thing freezes on me and I have to reboot yet again. I am totally stuck, anyone have an answer? I've managed to avoid or accept all the previous bugs, but this one is a total killer.

PS: I've been everywhere and done everything prior to this part. The only area left is behind the door with the two champion locks. I'm guessing that Cet is hiding somewhere beyond it, but I assume it won't open 'till I resolve the above Evil-Kerah issue?

Side question: The nearby room with the long slits in the floor and the blood stained centre and the two temple guardians and the windows onto the lave pit (you know the one I mean), does it have any purpose? No chests, no nasties, no levers, no nothing. Just wondering.

Finally broken the bug! You need to set up your characters to fight only before you activate the portal. While Kerah and Cet are present DO NOT touch any button other than Use/Give. Just keep hitting Kerah (she can take it) until she says she's thirsty then GIVE (not use) the holy water to her. Wait until she says her piece and leaves. Only then can you use the other buttons without freezing the whole game. Having replayed this section umpteen times before finally getting it right it does seem that it is the presence of Kerah herself which triggers the bug. It even froze after she was cured, but before she actually left.

PS: Another board (GameFAQs) suggested turning off all the sounds, tried that, didn't work.

I've now finished the game. Killing Cet was a piece of cake with both the Mavin and the Staff all black-fired up. I liked the bit at the very end when you finally get to see the narrator (hehe, no spoilers, if you want to know what I mean, you'll have to finish the game youself).

Make sure that gets reported...they might be able to get a fix for it in the unofficial patch they're working on. Include the solution...that sometimes helps narrow down the cause of the bug in the first place.

Done!