post #16 of 16
If the cake had been chilled and then sat in a humid place, it might have developed a film of water that **might** do this.

Otherwise the icing itself is too soft--add 4 pounds of sugar where it calls for 3.5 and also add a packet of Dream Whip (whipped dessert topping dry mix) or one 125 gram packet instant pudding mix. Both of these will absorb water and hold your cream together in high heat/humidity.