Iirc this happens when you have an entity that contains no solid brushes. When you use a model as an entity, for example a func_rotating you must include a small clip brush as part of the entity. It cant be just an origin brush and a model.
You have empty entity in your mapfile. For example some deleted doors etc. Omepn your entitylist (press "E") and look for func_entities without arrow next to it. If you find one, select it do a control. If it is empty (nothing is selected in 3D/2D look and is IS selected in entitylist), delete it and recompile your map. Repeat this process untill succes