In reply to Chris Hemedinger.

This post of yours does pretty much exactly what I'm trying to do (in reverse). I've tried hard-coding the variable:

%let download_to = /../2013_08/;

I can run %put _global_; after this and see that the macro variable is set how I want it to be set. When the Copy Files program runs, I still get the same warning that it cannot resolve. The EG process I'm running uses prompts that create separate macro variables that then run successfully where needed...it's only in Copy Files that they seem to not resolve.