Hey all, this is my first post here and from what I have read it looks like its a pretty good place. Here is my setup. Logitech harmony one remote, X10 style switch (made by X10 or Smarthome).
I'd recommend part# IR543 (receiver) and 2476S (on/off switch).
Here is my problem. I can control the switch to turn the light off but cant turn the light on. Anytime I push a button on the remote the IR receiver signals that it received the signal but doesnt pass it along to the on/off switch. Any suggestion, and thanks.

It sounds like you may have a noise problem on the power line and need a noise filter.  Things that can create noise APC battery backups, TVs and other electronic devices.  I had a problem with one of my older DirecTV Tivo receivers.  Be sure that the IR-543 isn't plugged into a surge protector.  Try unplugging devices until you identfy the problem.  Just turning them off will not solve the problem.

In other words, you have a typical X10 problem: some things work whilst others don't. Filters sometimes help but, in my experience, they often don't. Having these sorts of problems is commonplace with X10 and is why many people (including myself) eventually give up on it.