diff --git a/lib/roby/droby/plan_rebuilder.rb b/lib/roby/droby/plan_rebuilder.rb
index 7145dbea3..5743a83bc 100644
--- a/lib/roby/droby/plan_rebuilder.rb
+++ b/lib/roby/droby/plan_rebuilder.rb
@@ -344,7 +344,9 @@ def generator_fired(time, event)
             def generator_emit_failed(time, generator, error)
                 generator = local_object(generator)
                 error = local_object(error)
-                generator.plan.failed_emissions << [time, generator, error]
+                if generator.plan.respond_to?(:failed_emssions)
+                  generator.plan.failed_emissions << [time, generator, error]
+                end
                 announce_event_propagation_update
                 [generator, error]
             end