diff --git a/cinera/cinera_pre.js b/cinera/cinera_pre.js
index 60b12ec..da33c95 100644
--- a/cinera/cinera_pre.js
+++ b/cinera/cinera_pre.js
@@ -287,7 +287,7 @@ GetOrSetRule(SelectorText)
         {
             var cssRuleCode = document.all ? 'rules' : 'cssRules'; // account for IE and FF
             var Rules = StyleSheet[cssRuleCode];
-            var RuleIndex = StyleSheet.insertRule(SelectorText + "{}", StyleSheet.length - 1);
+            var RuleIndex = StyleSheet.insertRule(SelectorText + "{}", Rules.length - 1);
             Result = Rules[RuleIndex];
         }
     }