Better error message on "file not found"

question.py

@@ -109,7 +109,11 @@ class Questions(object):
 				self._gen_error(filename, "Section element %d is not a string (type %s found)" % (n, type(sec_filename)))
 
 			fpath = os.path.join(basedir, sec_filename)
-			sec_ysrc = self._get_yaml(fpath)
+			sec_ysrc = None
+			try:
+				sec_ysrc = self._get_yaml(fpath)
+			except (OSError, IOError) as e:
+				raise QuestionException("Error reading question file %s: %s" % (fpath, str(e)))
 			self._read_sections(sec_ysrc, fpath)
 
 	def _read_sections(self, ysrc, filename):