Error and can't drag and drop into some folders

I’ve been unable to determine what’s wrong. I’ll paste 3 screen shots that I hope will help explain what’s happening. I’m trying to drag and drop a folder outside of EagleFiler into a folder within EF. Sometimes the operation just won’t allow the folder or the files to be dropped and I don’t know why.
Here are the 3 screenshots


The above is the first setup in dropping the files. The highlighted folder is waiting to have the file (20120205.mp3) dropped into that highlighted folder.
The second is the folder activated and the list showing of existing files in the folder. And then I drop the file into the highlighted folder

The third shot shows the result of dropping the files. The empty error window appears, and the file disappears (It actually goes back on to the desktop).
I have been unable to determine the problem. I’ve tried creating another folder within EF and end up with the same thing happening.

HELP!

I only see 2, and the main EagleFiler window looks the same in both, as far as I can tell.

My guess is that you have the preferences set not to allow duplicate files, and EagleFiler is finding a duplicate and showing you this in the Errors window. If you make the Errors window larger you should be able to see this (or perhaps a different type of error).