"in a nutshell, Kies seems to have a MEMORY MANAGEMENT PROBLEM. If you Un Mount and pull the SD card (probably don't have to PULL it ...) Kies will work fine."
Two weeks it took for me to get Kies working reliably and syncing with outlook. Using win7 64 bit. Finally, I just had to unmount (and more importantly...LEAVE IT UNMOUNTED) and then connect usb in Kies mode. Tethering is even working. If I want acces to the sd card for file transfers I usb connect in mass storage mode and not use kies. I hope this helps others.