Some file and displays 36 permission related errors

I have a Mac Pro computer with 4 external hard disks. While trying to backup one of it which contains my iTunes library, I had a problem. The back up process gets stuck at some file and displays 36 permission related errors. On clicking the OK button, the whole copying process will get terminated. I have checked the files permission and cannot find anything odd.
The same thing occurs even after try removing the file at which it gets stacked and stops at some other file. I have also tried using software like “Super Duper” for force copying and even formatting the backup drive. But didn’t help. How can this be solved?
