Ah - XP with a 3Tb drive... then the problem is likely related to the special translator driver installed so XP can 'see' a 3Tb drive.
Just have him default his SAVE TO destination to his C: Drive, and then he can burn from there reliably, too. THEN if he wants to save those files to his 3Tb drive, move them there. I'll bet they'll play from there if he's using it as Media-Server storage.
But I am always suspicious of those translator packages - motherboards offer them as do most of the HDDs, too, but they're still extraordinary drivers for a base-level drive function. This demands absolute perfection on every function, and we all know how perfect our tech world is.
If and when he moves this 3Tb to a newer system, he might serious problems retrieving the 3Tb's data. He'll be safer to build that newer system first, install another clean hard-drive and transfer that data from his XP-based 3Tb onto that new system's clean drive - via some network cable. THEN install that 3Tb drive and see if the data's scrambled or not.