A couple other thoughts....
Some receivers have a very narrow angle that the IR receptor "sees". Like with a couple of my receivers, if I have the remote at a 45 deg angle, it doesn't work. When you're only 2 feet away, it makes it possible that you could be off by a considerable angle if you don't know exactly where the IR receptor is behind the plastic.
Also, is it possible that the IR extender is also picking up and repeating the signal when you're 2' away, so that the receiver is getting signal from 2 different places, possibly interferring? I have had problems with remote extenders at times, as they pick up interferrence from all sorts of things. I've used 2 or 3 different kinds, but usually use those RS/X-10 Powermid things. They have a little light that blinks when it's repeating, and often I'll see that light blinking when I'm not using any remote. Sometimes I've traced it to computer displays, even computer mouses (wired type, not the rf type). One time I found that if I moved my mouse over one specific window on my desktop, that it would activate the remote extender. Other times that thing has been blinking wildly, and I haven't been able to figure out what was causing it. Ie I've blocked the view from different directions, and couldn't figure out where the signal was coming from.
It's also possible that the signal from 2' away is just too strong. Some IR receptors can be overwhelmed by too much light from the remote. I have a learning remote that won't work if the remote it's learning from is too close. Also, the opposite is possible. It the remote is too weak, it's possible that the receiver has problems with the signal, but the receptor in the extender might be more sensitive. I have some remotes that work better through an extender, and I've decided that this is the reason. Also remotes often put out a weak signal if the batteries are low, and if you use rechargeable batteries, the voltage will ALWAYS be low (1.2 vs 1.5).
One interesting thing about remotes is that often they are so strong that the signals will go through things that you assume will block them. I had one remote that I could get to work even though holding my hand over the end of the remote. It would also work from behind the cloth of a shirt. Another time, I tried blocking a receiver by putting black construction paper over the front of the receiver to block the signal. Signal went right through 1 layer, 2 layers, 3 layers of construction paper. It wasn't until I put like 4 or 5 layers did it finally block the signal. Anyway, I think there can be great differences in the strength of different remotes and the sensitivity of the receptor in the receiver.
Just a few other possible parameters.
