TMDS570LS31HDK: After successfully downloading Hercules Safety MCU Demo, running any demo results in "Connection to the microcontroller has been lost" error. Restart produces same error.

A basic question: what evidence do you have that the download of the demo is actually taking place? Any LED changes at, during, or after the download? If the program is not talking to the device, it might classify it as 'connection lost'.

The download process reported successful download.

Ok, that was an inconclusive answer. But let me suggest the next question. Just a step back though, I think the manual would tell you what the LEDs would have been doing.

How sure are you that the demo firmware that was downloaded; is actually the right version for your hardware?

Not clear what you mean by "inconclusive." Here is what I did, following the instructions.
I'm running Windows 7 on a DELL laptop.
1. Purchased TMS570LS31x Hercules Development Kit.
2. Followed instructions in the Kit Quick Start Guide.
3. Installed two disks from the Dev Kit onto my computer:
a. Code Composer Studio IDE from included DVD (ver 7.3.0).
b. Hercules Development Kit software from the included DVD.
4. Attached USB mini-B connector from Dev board to USB on my computer.
5. Attached DC Power to 12VDC on board.
6. Launched Hercules Safety MCU Demo Software.
7. Hercules Demo Suite Launcher runs and shows Dialog:
Demo software not detected on microcontroller.
Warning: This will erase any data currently programmed into the microcontroller's flash memory.
Would you like to program the demo software into the uC's flash memory now?
8. Click Yes.
9. Hercules Demo Suit Launcher says, "Now Programming TMS570LS3x_demo_software.out" Wait.
10. Dialog 'Flash Programming Complete!' opens. Says:
Demo Software Programmed Successfully! Please press the PORRST button on the demo board
and then click the "OK" button below.
11. Press the S4 PORRST button next to the S3 RST button on the Demo board.
The 6 white led lights flash in pairs going up and down then all on and all off at about 0.5 sec rate.
12. Click OK on 'Flash Programming Complete!' dialog.
13. 'Hercules Launchpad [v 3.01.00]' dialog opens.
14. Click 'Ambient Light' button.
15. 'Ambient Light Demo' dialog opens.
16. Error dialog opens: "Connection to the microcontroller has been lost, please hit the PORST reset button
and try again. If this error persists please exit to the launch pad and rerun the demo.
17. Click 'Try Again'.
18. Same Error dialog opens: "Connection...lost..."
19. Click 'Exit'.
20. 'Ambient Light Demo' dialog closes.
21. Repeat Steps 14 to 19 for 'Ambient Temperature'
22. Close 'Hercules Launchpad [v 3.02.00]'.
23. Repeat Steps 14 to 22, identically.
24. Repeat Steps 6-23, identically.
Is this "conclusive" enough for you?

Between steps 8 and 9, do you see a small (possibly blue) LED near the mini-B USB flicker?
At step 10, do you wait to see that LEDs become stable?

I hope it works for you. I am not associated with TI in any way. Just making suggestions based on my experience with a RM46 HDK.

Neil,
My apologies. Thought you were TI. Thank you for your help.
101. Power-off board, Remove mini-B USB.
102. Attach power.
103. D9 lights blue; DS5 +12V lights blue; DS3 +5.0 lights blue; DS5 V3 lights blue; DS2 1V2 lights blue;
104. 6 white diodes light in pattern of Step 11.
105. Plug in mini-B USB.
106. D11 and D10 light faintly blue momentarily then go off.
107. D12 lights solid blue.
Bill

Unless you find it works now; we have likely gotten past the simple solutions.

Thanks. I noticed there are more recent versions. I'll try re-install with the latest versions for Code Composer and Hercules.