You are the first person to report problems with the drag'n'drop sort – can you give me some more details please.
Which browser are you using?
Can you try it with a different browser?
What are you seeing when you try to drag an image thumbnail?
This is what should happen. The thumbnail should move with your cursor and the other images move to fill the gap. Then if drag'n'drop sort is showing in the sort order box and you press 'Update', the screen should reload with your new sort order.
One other thing. Problems can arise if you do a drag'n'drop sort, then immediately go to the galleries index page to see the thumbnails and then hit the browser 'Back' button. If you go to the galleries index, then use the admin link in the top right hand corner to get back to svManager.
SimpleViewer Support Team.