Yes sure, if I remember correctly there were several fixes you have made for moving and deleting a file that is locked by the viewer pane. Consequently these error messages appear less frequently from version to version on my system.
Anyway in some rare cases DOpus still shows the error dialog on deleting files that are opened in the viewer pane.
Since it occurs this morning with the latest stable release I decided to post it.
If there's anything new to add, please add it to the existing thread so the information and history remains in one place.
But I think you may just need to close the viewer in this case. Doing anything which opens large exe files on slow media is liable to trigger locked files as well as potential delays from virus scanners.