Those files look like devices (they would normally be in /dev), and are files that you should NOT be modifying.
What is "ltspfs"? it sounds like a remote file system.
If you somehow unmount or stop ltspfs, and then try deleting again, does that work?
I don't think you shouldn't remove or change these files while ltspfs is running.
Ya, we are trying to mount usb flash drive for the user which runs on LTSP server. What happens is that, sometimes if the UID is changed for the user he cannot access his pen drive so if we delete it from the /tmp and add a line of his UID in /etc/mtab, it starts working. So there is no harm to delete from the /tmp