If your on windows 7 x64 bit, go to c:\Program Files (x86)\Samsung Electronics\ you will see a folder called "SWUpgrade for SPH-D720", right click and copy that folder. Then back out of windows explorer until you get to c:\, navigate to c:\Program Files\Samsung Electronics (if you dont have that folder, create it exactly as "Samsung Electronics"), right click and paste the "SWUgrade for SPH-D720 into the Samsung Electronics folder.
Basically, when we install this exe on a x64 bit system, the program installs in the 32 bit folder but is trying to run in the 64 bit. But of course the actual sw isnt in the right directory.
Uncle Jimmy says hello