Why do you want to drag files? Instead of dragging files, you can easily transfer files from your desktop to remote server using various file transfer services such as WebEx, gomeetnow, gotomeeting etc.
Before posting, please read how to report bug or request support effectively.
Bug reports without an attached log file are usually useless.
Thanks for your report.
I have sent you an email with a debug version of WinSCP to address you have used to register on this forum.