Yes, your pan was too hot.
Because your pan was empty when you heated it, it had minimal heat capacity, and could only lose heat by convection and radiation. Thus, it heated up quickly, and likely reached a much higher temperature than it normally could with food in it.
When you heat a pan with food in it, some of the heat is transferred to the food, and much of that heat is, in turn, lost when water in the food evaporates. This slows down the heating rate, and significantly reduces the peak temperature reached.
(Evaporating water is an extremely efficient method of heat transfer, especially at high temperatures, and even solid foods like meat and vegetables still contain quite a bit of water. Any time you put something on a hot pan and it steams or sizzles, that's the sign of water evaporating.)
Also, because you didn't have any oil or water or food on the pan, you had no easy way to gauge its temperature by eye. Normally, if you heat a pan with oil already in it, you can tell when it's hot enough just by looking at how the oil behaves. If you miss all the subtler signs, like the oil turning more runny and starting to form convection patterns, the point where it starts to change color and smoke is an unmistakable sign that you've definitely heated it too far.
With a dry pan, it's quite hard to tell just how hot it is. One trick I sometimes use is to sprinkle a few drops of water onto the pan and seeing how quickly it evaporates. (Don't do this if the pan already has oil in it!) When the drops evaporate all but instantly (but still briefly wet the surface, rather than exploding on contact or hovering over it), it's time to add the oil / butter.
Of course, the modern high-tech alternative would be to get an IR thermometer. I actually do have one, but I rarely use it — it's just quicker and easier to dip my fingers in some water and sprinkle it on the pan than to get the thermometer out of the cupboard.
I agree with @ElendilTheTall. Coconut milk and such based products do not have a long fresh shelf life. Personally, I would discard and not take the risk.
That said, I don't know where you are located and what standard practices apply. In a lot of cases common sense can apply as to how to handle.
Best Answer
There are multiple qualities, differently refined, on the market. Highly refined qualities that leave only the oil (various fatty acids) itself will have a very high smoke point and be suitable for high heat frying. There is a lot of saturated fats in coconut oil, which result in both the solid texture at low temperatures and the stability at high heat.
Unrefined or less-refined qualities will have other compounds left in, which can contribute to aroma (and possible nutritional benefits) but will also lower the smoking point and can actually result in an off taste and/or byproducts not considered healthy (why is off topic here).
Various smoke points are quoted, from 300°F for some unrefined varieties to 450°F for some highly refined ones. Exact smoke points likely depend on how exactly it was refined.
The exact same applies to olive oil, BTW: Highly refined varieties are known to be perfectly usable for high heat work, with the opposite being true of unrefined ones.