Brian,
I just noticed that when I put my hand in front of the IR543 when it was locked, it unlocked immediately. This was repeatable.
At this point, it looks like it is indeed some of the light from the CFLs still reaching into the front and confusing the IR543 ...
I pushed the IR543 further back into the rack so it will receive even less / no lights from the CFLs .. I will have to check again since the bulbs are now warm.
I have at least 12 IR components in the same location and none of them experience any problem from the CFLs receiving IR signals, from the same Sony RM-AV2500 universal remote that I am using to control the IR543.
I am inclined to say the IR543 is a piece of crap. Wish there was something else out there that didn't get this kind of interference .