Comment 3 for bug 665444

"File is not readable: .." means you don't have the right to read it !
Run "ls -lh ~/.recently-used.xbel.HFEL7U" to check rights and user/group.

Just to test that it is not about zero size file, create an empty file: "touch ~/abc.txt" and do a backup.

PS: no, for the moment you can't exclude files based on size.