When I try and move a discussion from one folder to another folder, I get the following message:

The move didn't take place: Duplicate name.

But there isn't another discussion with the same name title in the destination folder.

The issue is that the discussion's "filename" is the same as one at the destination, not the titles.

Web Crossing assigns a digit for a filename for URL's, and it starts at 1 for each folder. So it you move a discussion that is assigned a 123 to another folder that already has a 123, the move will fail.

To change it, just edit the discussion you want to move, and change the "Filename for URLs:" digit to some other value (may be a numeric, alphanumeric or alphabetical).