DirCopy() does not work at all

I'm working in AutoIT 3.3.6.1 to script a basic task I'll have to repeat on 50ish workstations.

I need to copy a directory and it's subdirectories and files (recursively) to a network share as a backup. For some reason, DirCopy() does not work at all.

I've tried running it on several different directories (thinking permissions issue, I'm Domain Admin account), tried doing a RunAs (again thinking permissions), and also put the

 #RequireAdmin 

tag to force the program to run on an elevated account. Nothing has worked. I can't even get it to copy empty directories.

DirCopy(@DesktopDir & "\SAMPLE\TEST1", @DesktopDir & "\SAMPLE\TEST2", 0)