It might be something simple on the Fog Storm 1700HD. Make sure that the low fluid indicator light is off. It's located in front of the fog machine. It will accidentally light up when the tank is not seated properly or if the floater gets stuck with in the tank. If this is not the case, then there's probably something wrong with the unit and you'll need to contact the Service Dept. at 800-322-6337.
As for the Mega Flash Dmx, are you running the unit stand alone or DMX?
Were you running both of these units on the same circuit? If so, that would put you over the limit on a 20 amp circuit and could cause problems.