Can't copy to NUL

[SupGuy]

I have someone reporting an application issue which has now been traced down to a piece of code that is outputing to NUL. I had him do a copy of a file to NUL from a command prompt using:

copy filename NUL

This resulted in an Access Denied error. However, I haven't been able to determine how you would control access to NUL to correct the problem.

Any tips to point me in the right direction?

Thanks in advance.