Error: There isn't any proper file in the source directory.

I intend to remove watermark from images, I have loaded the image and just as I start the processing, I get following error message:
Error: There isn't any proper file in the source directory.
I am not very technically sound, therefore my questions, what is the meaning of the above error message and how to resolve it?
Error: There isn't any proper file in the source directory.
I am not very technically sound, therefore my questions, what is the meaning of the above error message and how to resolve it?