I was having this same exact problem on all my laptops. It didn’t matter if I was using XP, Vista, or Win 7 on these laptops. Each time it would already get stuck after the exploitation stage then if i pressed the 2 buttons together it would maybe goto the next thing on the list. But no matter what, it would always get stuck on upload to ibec. It also didn’t matter if i had the power cord plugged into the apple tv device either, and didn’t matter if I had iTunes launched or not.
Then I tried iFaith dump on a windows desktop system with XP and it has worked everytime I try to do the dump!! Have been successful on at least 3 devices now!! And I do not need the power cord plugged into the outlet and also did not need iTunes launched either. It went straight to saving and asking me where to save the file to.
I think it was something to do with laptops not having enough power to the USB port to allow it to complete the dump process.
Try using a pc desktop and let us know if it works for you!