Hermaeus Mora quest Bug

[he3r0]

I have a slight problem with this one, maybe anyone can give me some tip...
I`ve already finished main quest line, all guilds and arena, and im almost done with daedric... and im playing on x360
I aleready have captured 7 souls of different races, but the spell that i`ve got looks like it stopped working... i can cast it, and i can see its visual effect on target, and if I cast this spell on shadowmere i can see message about invalid target, but if i cast the spell on any npc more then once i don't see pop up message that that character is already affected by the spell, also it looks that spell does not gather anymore souls, since i known that i don't have orc`s soul, i `ve already killed about 7of them, and all of them where under that spell (visually)and nothing happened... is there any way to reset that quest? what can affect that spell effectiveness?
thanks for answers.

[Belthan]

There is a known bug - if you hit more than one target with the spell, before you kill the first target, it stops working. Only fix on 360 is restore a savegame before the glitch happened. Fix for PC is in this thread:

http://www.gamebanshee.com/forums/the-e ... light=mora