aperture import files failed

In Aperture version 3.4.5, I m not able to import any file from a connected camera, memory card as I usually did.

I have set up that import directly when a camera is connected. This does not work at all.

Sometimes it send all the imported files directly to the trash. In this case the thumbnails are empty. I mean in black background.

Sometimes it shoes a warning window. "importing items completed with errors" "Aperture failed to imports the items listed below" and here are all the files to be imported.

Please I would thank any suggestion