I downloaded a components.cif file and filled the location of my .pdb files as shown in the picture below. It still showed error. The program usually opens but doesn't display the pdb files I want to study. I need professional advise please.
I had just encountered this problem and I changed the installation directory of Ligplot from C:\ to D:\ then this error dissappeared. Maybe because of administrater permission of writing file? I'm not sure my experience can help you.