diff --git a/propka/input.py b/propka/input.py
index 3971f12..b71b96f 100644
--- a/propka/input.py
+++ b/propka/input.py
@@ -99,7 +99,7 @@ def read_parameter_file(input_file, parameters):
     try:
         ifile = resource_filename(__name__, input_file)
         input_ = open_file_for_reading(ifile)
-    except (IOError, FileNotFoundError, ValueError):
+    except (IOError, FileNotFoundError, ValueError, KeyError):
         input_ = open_file_for_reading(input_file)
     for line in input_:
         parameters.parse_line(line)