To Kill an Empire help

[IRS Tax+ Subscriber]

I have done this before, but it didn't work. So I'm wondering if there is anyone else to help me please.
Basically, in the dark brotherhood quest line, when you murder the emperor. once I finish the soup, and walk up the stairs, the game shuts down. I have the unofficial skyrim patch. I have tried tcl, and when I use tcl, Gianna is frozen. I need help please!!

[Ceejay]

I have a similar issues, Iwhen I go to follow her she just spins on the spot, I have finished this quest at least 5 times before, so no idea what is going on, and not a vampire, reloaded multiple times.