Files uploaded with SmartFTP can't be seen by other progs

I uploaded directory of files using smartFTP to my website, as I've done other times in the past.

It was a simple drag and drop from the local drive (cd, drive D:). I dragged the whole folder and it created a folder named d: as a subfolder on my web server.

After it was finished, I checked that the files were accessible using SmartFTP, and they were. All is well, I thought.

But when I tried to access the files using http, I kept getting 404 errors. So I tried renaming the directory (named "d:") using the vdeck software portal that I administer my site with. I couldn't do it. I also couldn't open the folder.

Then a user reported that although they could see the D: folder in their FTP view--not using SmartFTP, using a different client--they couldn't open the folder.

So I accessed the folder with FireFTP (firefox plugin) and had the same issue. Tried with SmartFTP, and everything works fine. Even renamed the folder in SmartFTP. Went back in with FireFTP, and the new name does not show up. Closed SmartFTP, reopened it, went back in: new name is there, files are accessible. Should be noted that this is on a different machine than the upload took place on.

So what's going on? How come SmartFTP can see the folder and access the files, but other clients can't?

Any help appreciated.

Jason