diff --git a/BUGS.md b/BUGS.md
index a8e0d26..7b93d45 100644
--- a/BUGS.md
+++ b/BUGS.md
@@ -1,7 +1,6 @@
 
 BUGS:
 
-- se refs de um topic estao invalidos, nao carrega esse topico. devia haver um error nos logs a indicar qual o ref invalido.
 - forçar reload das perguntas sem ter de deitar abaixo o servidor.
 - topicos virtuais nao deveriam aparecer. na construção da árvore os sucessores seriam ligados directamente aos predecessores.
 - Criar outra estrutura organizada em capítulos (conjuntos de tópicos). Permitir capítulos de capítulos, etc. talvez usar grafos de grafos...
@@ -34,6 +33,7 @@ TODO:
 
 FIXED:
 
+- se refs de um topic estao invalidos, nao carrega esse topico. devia haver um error nos logs a indicar qual o ref invalido.
 - link directo para topico nao valida se topico esta unlocked.
 - templates not working: quesntion-information, question-warning (remove all informative panels??)
 - enderecos errados dao internal error.
diff --git a/demo/demo.yaml b/demo/demo.yaml
index 9e8158e..6e9f858 100644
--- a/demo/demo.yaml
+++ b/demo/demo.yaml
@@ -14,7 +14,7 @@ path: ./demo
 topics:
 
   # topic without dependencies
-  math:
+  matha:
     name: Matemática
 
   # topic with one dependency
diff --git a/learnapp.py b/learnapp.py
index f8e9b45..01c622e 100644
--- a/learnapp.py
+++ b/learnapp.py
@@ -297,7 +297,7 @@ def build_dependency_graph(config={}):
         # if questions not in configuration then load all, preserving order
         if not tnode['questions']:
             tnode['questions'] = [q['ref'] for q in loaded_questions]
-
+        
         # make questions factory (without repeating same question)
         tnode['factory'] = {}
         for q in loaded_questions:
diff --git a/tools.py b/tools.py
index e3f06db..4ab1931 100644
--- a/tools.py
+++ b/tools.py
@@ -133,25 +133,24 @@ def md_to_html(text, q=None):
 # load data from yaml file
 # ---------------------------------------------------------------------------
 def load_yaml(filename, default=None):
+    filename = path.expanduser(filename)
     try:
-        f = open(path.expanduser(filename), 'r', encoding='utf-8')
+        f = open(filename, 'r', encoding='utf-8')
     except FileNotFoundError:
-        logger.error(f'Can\'t open "{script}": not found.')
-        return default
+        logger.error(f'Can\'t open "{filename}": not found.')
     except PermissionError:
-        logger.error(f'Can\'t open "{script}": no permission.')
-        return default
+        logger.error(f'Can\'t open "{filename}": no permission.')
     except IOError:
         logger.error(f'Can\'t open file "{filename}".')
-        return default
     else:
         with f:
             try:
-                return yaml.load(f)
+                default = yaml.load(f)
             except yaml.YAMLError as e:
                 mark = e.problem_mark
                 logger.error(f'In YAML file "{filename}" near line {mark.line}, column {mark.column+1}.')
-                return default
+    finally:
+        return default
 
 # ---------------------------------------------------------------------------
 # Runs a script and returns its stdout parsed as yaml, or None on error.
--
libgit2 0.21.2