nfts is still not fully supported as far as i know. so you can't make changes to it even as root user. but there are ntfs tools for linux with which it should be possibile to make changes. yet, they are not safe, i.e. can lead to data loss...
you have two possibilities:
1. format your usb to fat32
2. get the ntfs tools running and try them
p.s.: i don't know if the latest kernel version does support ntfs by default? i doubt it though.