I seem to be stuck on this mission. I have made it to the main chamber and have placed the Gauldur Amulet artifacts to be reforged which has summoned the Brothers. I have beat Mikrul many times and when Sigdis begins his battle I get to a certain point and he teleports back to the top of the alter with his brother Jyrik and they are locked there and I am unable to proceed any further. I have gone back to a prior save many times before I have to use the Emerald claw to gain passage. The only other thing that I can think of is I was on a prior Winterhold college quest with Tolfdir before I changed quests. Any suggestions or help would be greatly appreciated. Thank you......... Soul

As you defeat the brothers, they should appear back above the altar. It sounds as if the third brother is not being activated to fight you. sometimes moving around in the chamber will get things moving faster, but I've never had a long-term issue with it.

Check http://www.uesp.net/wiki/Skyrim:Forbidden_Legend#Bugs for all the known bugs and their possible solutions.

Cool thank you both. One does turn into ash pile once back at alter. Now I know. Just have to get the 360 to update the latest patch. hopefully if the patch works I don't have to start a new file to continue.