Hi Michael,
That was it! From the Device Manager under Windows 7 I installed the drivers from C:\ti\TivaWare_C_Series-2.0.1.11577\windows_drivers and it now enumerates property under both dfuprog and the LM Flash Programmer. I'm feeling very stupid for missing this but am glad you were able to find the problem. Thanks so much!
We all really appreciate your help and are glad just to be off and running again.
Gareth