iPod - iPod 5th gen problem, won't sync because of permissions

I have had my iPod classic 5th gen for over a year and my warranty has ended, but I still want it to work. I am having problems syncing, it gets to about 14.5gb then a pop up comes up saying that I haven't got the permissions to copy the rest of my music.

It then says to check the Itunes folder and music folders in my library to see if any have any permissions, but I have hundreds of folders and no time to go through each individually.

This problem has only just started a week ago and I haven't added any new music to my library for about 3 weeks.

I am so confused whether this is a genuine problem or that my iPod is broken. Please does anyone have any suggestions. Or even better, can anyone tell me a way of view folders with read only permissions?