Vista File Mgmt can't find items that exist

I have a problem similar to several posted a few months ago.
I have a directory with 39 *.avi files that I want to move as I'm organizing my drives and files, and also making backups. Their sizes are from a few MB to a couple of hundred MB.

They display in the source directory, and they play on Media Player.

When I try to copy them with Explorer, I get the message "Could not find this item. This is no longer located in J:\Grand Canyon... Verify the location and try again."

I've renamed them to comply with DOS filename restrictions. I ran CMD as an administrator. The files appear, with the appropriate sizes. When I tried to copy them within the CMD window, I get the message "The system cannot find the file specified." for every one of the files.

I had previously, under XP, made copies onto a randomly selected HD. So the files exist in two locations, they run from both locations, I can rename them and see their properties. But Vista File Management can't "find" them.

Any suggestions on how I can copy/move them?