diff --git a/code/components/jomjol_flowcontroll/ClassFlowControll.cpp b/code/components/jomjol_flowcontroll/ClassFlowControll.cpp
index 454ac821..d7bcf23a 100644
--- a/code/components/jomjol_flowcontroll/ClassFlowControll.cpp
+++ b/code/components/jomjol_flowcontroll/ClassFlowControll.cpp
@@ -397,7 +397,7 @@ string ClassFlowControll::GetPrevalue(std::string _number)
         return flowpostprocessing->GetPreValue(_number);   
     }
 
-    return std::string();    
+    return std::string("");    
 }
 
 std::string ClassFlowControll::UpdatePrevalue(std::string _newvalue, std::string _numbers, bool _extern)
diff --git a/code/components/jomjol_flowcontroll/ClassFlowPostProcessing.cpp b/code/components/jomjol_flowcontroll/ClassFlowPostProcessing.cpp
index 527f5cb6..cede216d 100644
--- a/code/components/jomjol_flowcontroll/ClassFlowPostProcessing.cpp
+++ b/code/components/jomjol_flowcontroll/ClassFlowPostProcessing.cpp
@@ -80,12 +80,15 @@ string ClassFlowPostProcessing::GetPreValue(std::string _number)
     int index = -1;
 
     if (_number == "")
-        _number = "default";
+        _number = "default"; 
 
     for (int i = 0; i < NUMBERS.size(); ++i)
         if (NUMBERS[i]->name == _number)
             index = i;
 
+    if (index == -1)
+        return std::string("");
+
     result = RundeOutput(NUMBERS[index]->PreValue, NUMBERS[index]->Nachkomma);
 
     return result;