Well, 3 stores were out of Serial to USB adapters, so I tried again on my crappy PC.

I finally stumbled onto the answer - The RC3200 application was not saving the .ncf file correctly. Basically it was failing to put the bitmap files in a Bitmaps\ folder.

Steps I used to fix:
1) Rename the bad ncf file with a .zip extension
2) Unzip the contents to a folder using WinZip
NOTE: Winzip complains about a bad Bitmaps\ folder entry. I just told it to continue
3) Create the Bitmaps\ folder and put all the images into it
4) Zip up the fixed structure
5) Opened the zip file in WinZip and added this comment to the file:
Type:001
Version:001.000

This was the key part to get the RC3200 to open the file correctly.

6) Renamed the file back to a .ncf file

*phew*

I still have no idea why this once PC is so fubar'd, but at least I can upload/download now.