1) Those IR receivers you linked to on amazon.com are complete junk. In addition to them being crappy to begin with, they are both 5V IR receivers - they are not really compatible with Xantech's standard 12v system. So not surprising they don't work at all.

2) IR blasters are very hard to setup correctly. Meaning they have to be installed in such a way, as to face all the equipment you are trying to control. You say the equipment is in a rack, unless you have put the IR blaster in a position 5-10 feet in front of the rack where it can actually send signal to everything, how is it you expect this to work?

3) You wire all the IR receivers together on the input terminals of the 791-44 (+12VDC, GND, IR IN). Plug your power supply in (this block should be the ONLY place a power supply is plugged in).

4) Your IR emitters will plug into the outputs to each device. You have 10 outputs. How many devices are you trying to control? You use dual emitters on some outputs will double the amount of components you control. They would make 20 devices. If you have more than that, you are seriously using the wrong approach to control in this setup.

5) Besides there 100% not needing to be a reason for you to be using a 781-44 when you have a 791-44, the actual problems would have to be diagnosed after you have the setup correct. If there are any issues at all after you get it setup correctly.

[NOTE]: Make sure you are using the correct power supply for the 791-44. 782ERGPS which supplies 1000mAh. NOT the 781ERGPS which only supplies 200mAh (that is for a regular 781-44).