Please check does folders contains any .xmp files from which you are trying to import.
You can open the finder window and check the folders in them for any .xmp files
No that should be any problem.
Can you try again with the memory card
Also check if you are able to import the images from the desktop.
I tried the SD card again--same story, just a blank import dialog.
Images from the desktop will not import either. Import dialog is just blank.