Newbie question about how IR extenders work...

In my media room, my A/V equipment is not all in one place (e.g. projector is behind me, receiver is off to the side, etc.) so sometimes my Harmony remote will 'miss' a component, and I end up having to go through the remote's help menu more often than I'd like.

I'm wondering if an IR extender (IR=>RF=>IR) will solve the problem. My concern is, wouldn't that cause a conflict whenever my A/V components *do* get the initial command directly from my remote? With the IR extender re-issuing the command, wouldn't the components then get the same command twice?

For example, if my Harmony remote successfully issues the command to toggle Power On for my DVD player, but then the IR extender issues the same command, won't this toggle my DVD player back OFF again?

Well unfortunately my Harmony remote is not the 1000 (it's an earlier model -- can't remember which one at the moment), and doesn't have RF capability. I was referring to some of the after-market extenders, like this one: http://www.amazon.com/POWERMID-Remot...0348179&sr=8-7