Can't drag and drop to a network folder

Hi all,

I'm having a strange issue with one of my accountants. In the Accounting shared drive, he can cut a file and paste it to his desktop. He can then copy this file from the desktop and paste it back to the shared drive.

However, if he tries to drag-and-drop the file (instead of pasting it), he gets the message: "Destination Folder Access Denied" "You require permission to perform this action".

I had him log into a different computer and everything functions normally. He can cut, paste, drag & drop without any problems.

I have checked the computer group and disabled the firewall. No luck. I've checked and double checked his permissions. No luck. His computer is relatively new...he did inherit it from his predecessor...but I can't imagine that would interfere with this type of permissions.

He has a Windows 7 computer and we run Windows Server 2008 R2.

I've never seen this error before. Thanks in advance for your help.