Those photos are already in your catalog in some other folder on your drive.
Select the All Photographs option in the Catalog section of the Library modules left hand panel then open the Filter bar, Text option, and type in one of those 32 photos file names. I bet it shows up. Then Right Click on it and selct Show in folder in Library to see what exact folder it is in.
You have already imported these images to Lightroom's catalog, probably by ACCIDENTALLY using COPY, so Lightroom knows about the copy in a different folder, and will not allow you to import the photo again.