Parsing error crash.

execution.py

@@ -374,6 +374,7 @@ def validate_prompt(prompt):
             print(traceback.format_exc())
             valid = False
             reason = "Parsing error"
+            node_id = None
 
         if valid == True:
             good_outputs.add(o)
@@ -381,6 +382,7 @@ def validate_prompt(prompt):
             print("Failed to validate prompt for output {} {}".format(o, reason))
             print("output will be ignored")
             errors += [(o, reason)]
+            if node_id is not None:
                 if node_id not in node_errors:
                     node_errors[node_id] = {"message": reason, "dependent_outputs": []}
                 node_errors[node_id]["dependent_outputs"].append(o)