diff --git a/lib/controller/controller.py b/lib/controller/controller.py
index 2c5886914..c7b17c819 100644
--- a/lib/controller/controller.py
+++ b/lib/controller/controller.py
@@ -291,8 +291,9 @@ def start():
                     condition = True
 
                 if condition:
-                    conf.matchRatio = kb.paramMatchRatio[(kb.injPlace, kb.injParameter)]
-                    setMatchRatio()
+                    if kb.paramMatchRatio:
+                        conf.matchRatio = kb.paramMatchRatio[(kb.injPlace, kb.injParameter)]
+                        setMatchRatio()
                     checkForParenthesis()
                     action()