Hi. I am a self taught cake decorator starting when I was 13 years old and have been decorating cakes for many years. I am by no means a professional at it as I do it mainly for friends and family. This past weekend was  my daughter's wedding. I decorated a beautiful cake and tried putting filling in between the layers on 2tiers. I'm not sure if this was the problem or not and I have read  several different blogs since this weekend. My tiers with the filling kept  sagging, and I originally thought it was a dowel rod problem. Disassembled the cake and placed larger rods ;and which now I know that was a big mistake.  After the second assembly the cake still looked great but on the way to the venue it started falling apart and could not be repaired. I also noticed that the icing was peeling off from the side. I did not use the zero trans fat Crisco because I have had problems with that in the past.  The cake seemed too moist and just completely fell apart. Did the filling soak in and cause the cake to get too moist? This was only my 2nd time filling a cake. It was a yellow cake recipe that I have used for 25 years. Nothing was different except the filling. Please help. It was a disaster. 

Sounds like you really had more than one problem - so very sorry! :(   

......Disassembled the cake and placed larger rods ;and which now I know that was a big mistake.......

Why do you know this was a big mistake.   It's the support system that holds up a cake, even if the tiers are falling apart.   If the cake was too moist (in my book that is impossible) it sounds like maybe it waS'nt baked enough.  You don't mention what you used for filling.   Most of us have used many different kinds of fillings and NO it does not make the cake 'too moist' and fall apart.  Maybe you used too much filling.......did you put a dam around the layer to hold it in and not put filling above that?  With the informantion giving it's hard to help you more than that.   Any pictures, both before and after it fell apart.   Oh, BTW: if icing peeled off, it sounds like it was too stiff....needed to be a bit more creamy &/or soft.  What icing recipe did you use?   

I'm sorry this happened for your daughters wedding; I'm sure she understood. Do you have before and after photo's; its hard to say without seeing what happened. 

What kind of filling did you use? And was the cake cake chilled for transport?

Did you create a buttercream dam so the filling would stay inside of the cake and not seep out of the sides?