Trouble applying my flat outline to model

Hello,

I'm having some trouble getting my flat dieline to apply properly to the model.  No matter how many times I try the flat file will not wrap properly around the model.  I try to scale and move the outline up to fit and even scale the model down, but nothing seems to work.  I ended up just placing each side on separately, which works for now but I need to know why it's not working.  Is there a specific file type that the dieline needs to be in?  Is there a better/more specific way to ensure that the model is the correct size other than the x y z?

Please help!!

Best,

Ashley