Andrea,
There are 41 JPEGs in your file list and by default, they'll be paired with their corresponding CR2 files. By that account, the number of files would be 4430 files. You can un-join the RAW and JPEG files from the View menu and you should then see PM reporting 4471 files.
Now if after that, some of your images still don't show up, it would be interesting to move those files to their own folder separate from the others and then browse that folder. Do none of the images show up then?
-Kirk