Odd... I don't have any other reports of such a problem.
Are you using version 1.8.2 ?
Which Mac OS X are you using?
PPC or Intel Mac?
There are changes for drag and drop introduced in v1.8.0 specifically for Snow Leopard compatibility. There are no other changes to drag and drop since then, so I assume you previously used v1.7.2 ?
Try with v1.7.2 to see if there is any difference:
http://www.yummysoftware.com/archive/1.7.2/(Note that you don't need to install the old version, just double click it from the downloaded disk image)