Make sure that your version of kiss is up to date. It just updated but i forget the exact version number. Definitely make sure that you have the updated drivers. I had to use a macbook for my update. It hung on the Kies update so i restarted it and updated the drivers after rebooting kiss through an option in the toolbar. After that I was rollin.
Im experiencing the same problem for the second time. Basically your gonna need to find an actual warranty store and you can do that by calling At&t. At that store theyll be able to flash your device back to the fingerbread firmware. Apparently its an issuse with Samsung and high request volume of the new firmware, also they are doing maintenance on software and to call and check before attempting to download again.
well i ended up having to completely wipe out my phone and start over i dont even know what software I am running right now. its all black and such i like how it was before when i fist got it and to be honest i have been thinking alot lately i might go back to iphone