Okay. First, I assume you are using Win XP or Vista, right? The "MS DOS prompt" has been a command shell for quite a while. But anyway, does your code change to the correct directory? The scheduled copy might be starting in a default directory (like your user folder), and thus be in the wrong place.

I don't think this is Perl problem, since you've demonstrated it works. I suspect it's either a permission problem, or it's starting in the wrong directory. Try checking the current directory from the script that's being run from the Windows Task Scheduler. Also try adding some lines to create or delete files, along with the result.

--marmot