fillet spline extruded to solid = endless loop

Draw a spline - 6 points or so is fine. Extrude it as a solid. Fillet the top edge. When I click the top edge at the Select an edge: prompt the application seems to go into a loop consuming all available CPU forever until I terminate the process. It shuld just highlight the edge.This is very reproducable, although on one attempt I did get an error message that said something like:Cannot complete sheet - blend may be too bigI have no idea what that means.Thanks