Are you able to PC-control the 780?Because after hearing about your problem, I decided to download the same demo for my 780. After a few glitches, I'm now able to run the 780 on my PC. (But I haven't tried the SMARTSCAN yet.)
The important thing is to make sure the letters 'RMT' shows up on your radio display. That means it is on remote via PC. The way to get the RMT is to press the E on your radio keypad.
Let us know. We need to zero into this problem, once we know exactly how you're setting everything up.
TheVibeRAIDER