Windows uses the file system FAT and NTFS. Therefore Windows can't read hard drives that are "Mac OS Extended". You are going to need to copy your iTunes folder to a hard drive that is FAT.
Then, you can try to copy your iTunes folder directly to Windows. If this doesn't work tell iTunes (on your PC) to add all songs, videos etc. from the FAT drive to your PC. This way, you would just need to create all your playlists again, manually.