I hadn't heard that MDMA could cause a shut down of the body's cooling process. Where did you see this?
I've never heard anything about it affecting the body's cooling system. It is, however, a stimulant, all stimulants raise body temperature to some degree. Couple that with non-stop fast-paced physical acitivty (dancing) and a crowded venue with little hydration available, and you have the recipe for heatstroke.
Watch Out For Heat Stroke