If you are using AutoMapper (a great tool btw) together with DevExpress XPO its posssible you run into this error
automapper needs to have a constructor with 0 args or only optional args
var autoMapperConfig = new MapperConfiguration( cfg => cfg.CreateMap<SourceObject, MyXpoObject>(). ConstructUsing(x => new MyXpoObject(mySession) ) );
Sure, no rocket science but I had to search a while.