Symptoms
This error keeps surfacing: "Server Error: Could not load file or assembly 'Control' or one of its dependencies. The system cannot find the file specified."
Community Control:
-DragAndDropFile:Input=DragAndDropControl.DragAndDropFile.Control, Control
Diagnoses
Perhaps you are experiencing an issue with the DragAndDropFile control's "FullName" as per:
Resolution
http://community.k2.com/t5/K2-blackpearl/Drag-and-Drop-Upload-Control/ba-p/63942
Please know that K2 community projects/custom projects are usually not supported by K2 Support and the owner of the controlcomponent should be contacted should you run into any issues.