Add error "Cannot read file"

src/main/java/com/sheepit/client/Error.java

@@ -54,6 +54,7 @@ public class Error {
 		IMAGE_WRONG_DIMENSION(26),
 		CURRENTLY_HEADLESS(28),
 		DENOISING_NOT_SUPPORTED(29),
+		CANNOT_READ_FILE(30),
 		
 		// internal error handling
 		NO_SPACE_LEFT_ON_DEVICE(100),
@@ -222,6 +223,8 @@ public class Error {
 				return "The rendered image had the wrong resolution. This project is configured incorrectly. Switching to another project.";
 			case CURRENTLY_HEADLESS:
 				return "Blender can not open a display to create an OpenGL context needed for EEVEE/GPencil. Will try another project in a few minutes.";
+			case CANNOT_READ_FILE:
+				return "Blender failed to read the project files. Will try another project in a few minutes.";
 			default:
 				return in.toString();
 		}