Simple inverter circuit acting weird.

I have a strange problem involving an inverter. I want it to do what (I assumed) inverters are meant to do.

http://i.imgur.com/DlWipGo.png

When my system powers on, I want a green light to turn on, but when a laser is activated, I want the green one to turn off and a red one to turn on instead. So what I did is I put the system power into the Vcc of my inverter, and the laser’s power voltage goes into the input. When the system turns on, I assumed that the inverter’s output would emit 5v. And only when the laser emits it’s 5v would we see the output turn off (and the red one turns on).

Instead I’m seeing something weird. The input spits out it’s own 1.6 volts, even when nothing is plugged into it. While the output stays around 0.04 volts. I tried to use a 10K pulldown resistor to force the input to zero volts, but it stays at 1.6v. If I pull the input to ground with a bare wire, the output will go as high as 3.3 (which is something, but still weird considering I’m powering the chip with 5.3v). But if I leave this super-pulldown resistor the chip starts getting very very hot, like I’ve created a short somewhere.

This is the internal diagram of the inverter chip I’m using. http://i.imgur.com/VoATagq.png I don’t see why shorting the input straight to ground would cause it to heat up. At worst, he’s got that 1.4K resistor that’s limiting the current. I'm proving the power from the digital output of my arduino (I plan on using transistors to power the lights), and I remember reading that arduino is good in supplying up to 20 mA from it's ports. Could it be that the chip is trying to pull more power than the arduino can supply? But if that was the case I imagine it would be the arduino that would heat up, not the inverter.

Anyone who might have a clue as to what's happening and be willing to explain it to me? I'd very much appreciate it.