No Christmas Tour Photos Today :(

The Fredericksburg Candlelight Christmas Tour was this past weekend.  Every year, during the second weekend in December, a number of historic houses in town are decorated for the holidays and are open to the public ... with hosts and hostesses in each room telling about the house, the history, and some of the more interesting furnishings and decorations. 
 
The Husband and I always volunteer to do a shift in one of the houses ... on Saturday, he was on the porch of our assigned house telling about the architecture and the the history of the original family, and I was showing guests the living and dining rooms.  On Sunday, we went out to breakfast and then headed to town to be among the first in line to tour the rest of the houses.  I had my trusty Nikon D70 camera with me, and I took lots and LOTS of photos.  The day was cloudy and a bit drizzly, but I still think I got at least a few really nice shots of the outsides and decorations on the tour homes.
 
Earlier this morning, I hooked up my camera to download the pictures.  Nothing happened.  I checked the camera's playback, and I got this:

(This is a simulation, because my iPad camera wouldn't set its exposure compensate for the brightness of the LCD screen to photograph the actual words.)

 

 

I took about a hundred photos yesterday, and I know the images were there as I was taking them, because I checked the playback numerous times to make sure I got the shots I wanted.  Somehow, the photos vanished.

 

This happened to me once before ... while I was in Sacramento at the rose conference in October.  I hooked up the camera to my laptop to download my photos, and the last 75-or-so of my 400+ photos from that day disappeared.  Gone. 

 

I suspect that it may be the memory card.  I have three that I use with this camera, and I wonder if this was maybe the same card I was using that day in California.  Just in case, I have put that one aside and now I will go back to using my tried-and-true original 512mb card that I KNOW has never let me down.

 

(Just so you know, I don't use any camera software to download my photos.  I read the files directly using a USB cable and Windows Explorer, cutting and pasting them into the destination folder on my computer.  This morning, there were no files on the card at all.)   

 

I really wish I could have shared the tour photos with you.  I can get streetside shots again on another day, but many of the photos I lost were views of the parts of the outside of the houses that are only available if one is actually IN the private parts of the yards.  No interior photography is allowed, but I did sneak a few shots through the windows while I standing outside.

 

Have you ever had this happen to you?  If so, did you ever find out what caused the problem?