what do I have to do to make them work while the foobar window is NOT open

Download the intellikey program by Microsoft, then remap the keys so that they run the program's commandline instructions instead of Foobar's hotkey system .

It's somewhere on the forum..

edit: http://www.hydrogenaudio.org/forums/index....c=54963&hl=

wow, thanks! It worked!

edit: I didn't even have to remap the keys, I just installed, and it worked!

I know the other solution mentioned worked, but perhaps you did not have the MM shortcuts set to "Global" in the preferences. You need to do that to get the shortcut keys to work when fb2k is minimized, or not the window of focus.