How do I turn this into a sheet metal part

I am having trouble modeling the attached part in the sheet metal environment. I have created and attached a part file using normal modeling commands that I need a flat pattern for. I have tried to use the convert to sheet metal command but I keep getting an error "Cannot be a bend edge as there is a face for this edge which is non-planar". Can anyone give me another direction to try?

Thanks,

SW 2010 SP4

SolidworksSheet Metal