Como puedo arreglar error que me da creando una incapacidad?

Estoy creando una incapacidad y me surge el siguiente error:

System.Data.UpdateException: Entities in 'AppDataContext.Incapacidades' participate in the 'fk_expexp_accixe' relationship. 0 related 'Expediente' were found. 1 'Expediente' is expected. at System.Data.Mapping.Update.Internal.UpdateTranslator.RelationshipConstraintValidator.ValidateConstraints() at System.Data.Mapping.Update.Internal.UpdateTranslator.ProduceCommands() at System.Data.Mapping.Update.Internal.UpdateTranslator.Update(IEntityStateManager stateManager, IEntityAdapter adapter) at System.Data.Objects.ObjectContext.SaveChanges(SaveOptions options) at Aseinfo.VH4.Data.AppDataContext.SaveChanges(SaveOptions options) in c:\clientes\AEI\VH4\Data\Model\AppDataContext.cs:line 81 at Aseinfo.Infrastructure.Base.Entity.GenericEntityRepository.SaveChanges() in c:\clientes\AEI\Infrastructure\Base\Entity\GenericEntityRepository.cs:line 201 at Aseinfo.Infrastructure.Base.Entity.EntityServiceBase`2.SaveChanges() in c:\clientes\AEI\Infrastructure\Base\Entity\EntityServiceBase.cs:line 519 at Aseinfo.Infrastructure.Base.Entity.EntityServiceBase`2.DoInsert(T entity, Boolean saveChanges, Boolean bypassWorkflowInitialization) in c:\clientes\AEI\Infrastructure\Base\Entity\EntityServiceBase.cs:line 818 at Aseinfo.VH4.Acciones.Controllers.IncapacidadController.SaveIncapacidad(Incapacidad entity, Nullable`1 codigoEmpleo, Nullable`1 codigoEmpleoSolicita, Nullable`1 codigoTipo, Nullable`1 codigoRiesgo, Nullable`1 codigoClinicaMedica, String codigoVisualTipoPlanilla, String codigoVisualPlanilla, Nullable`1 codigoIncapacidadProrrogar, Int32 codigoCompania, Boolean inserting, Nullable`1 iniciaFlujo) in c:\clientes\AEI\VH4\Acciones\Controllers\IncapacidadController.cs:line 641 at Aseinfo.VH4.Acciones.Controllers.IncapacidadController.Create(Incapacidad entity, Nullable`1 codigoEmpleo, Nullable`1 codigoEmpleoSolicita, Nullable`1 codigoTipo, Nullable`1 codigoRiesgo, Nullable`1 codigoClinicaMedica, String codigoVisualTipoPlanilla, String codigoVisualPlanilla, Nullable`1 codigoIncapacidadProrrogar, Int32 codigoCompania, Nullable`1 iniciaFlujo, DateTime fechaInicio, Nullable`1 fechaFinal) in c:\clientes\AEI\VH4\Acciones\Controllers\IncapacidadController.cs:line 329 at lambda_method(Closure , ControllerBase , Object[] ) at System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters) at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters) at System.Web.Mvc.ControllerActionInvoker.<>c__DisplayClass15.<InvokeActionMethodWithFilters>b__12() at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodFilter(IActionFilter filter, ActionExecutingContext preContext, Func`1 continuation) at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodFilter(IActionFilter filter, ActionExecutingContext preContext, Func`1 continuation) at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodWithFilters(ControllerContext controllerContext, IList`1 filters, ActionDescriptor actionDescriptor, IDictionary`2 parameters) at System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext controllerContext, String actionName)