This worked beautifully! My buttercream is even more beautiful than when i originally made it! This is from one of the posts above:
Italian Buttercream is a simple "water and fat emulsion". Sometimes the emulsion breaks, resulting in a buttercream that looks broken and curdled. However, it is very easy to fix.
First, if the buttercream is cold and broken, separately melt about 25% of the mixture, return it to the remainder and then rewhip -- it should come right together.