Tell us about yourself!
It would be, but most likely it's hydrated iron oxide (i.e a molecule of iron oxide that has water chemically bonded to it). To avoid the danger of steam explosion the water should be driven out of it by drying it in an oven or something.
I'd grab a multimeter and check if the supply voltage is good. If it is then I'd connect it between the power supply and the heating element to see whether any current passes through. If it does (but it's too low e.g. in the ranges of mA or tens of mA) then probably the resistance of your carbon tape is probably too high for the given voltage (it doesn't push through enough current through the tape). If that's the case then you'll probably need some other heating element with less resistance (shorter/thicker/wider carbon tape or some nichrome wire instead) I'm afraid.