diff --git a/JsonPreprocessor/CJsonPreprocessor.py b/JsonPreprocessor/CJsonPreprocessor.py
index 0f04adc0..6fe6e19b 100644
--- a/JsonPreprocessor/CJsonPreprocessor.py
+++ b/JsonPreprocessor/CJsonPreprocessor.py
@@ -198,7 +198,8 @@ def __init__(self, syntax: CSyntaxType = CSyntaxType.python , currentCfg : dict
         self.jsonCheck = {}
         self.JPGlobals = {}
         self.pythonTypeError = ["object is not subscriptable", \
-                                "string indices must be integers"]
+                                "string indices must be integers", \
+                                "list indices must be integers"]
 
     def __getFailedJsonDoc(self, jsonDecodeError=None, areaBeforePosition=50, areaAfterPosition=20, oneLine=True):
         failedJsonDoc = None
@@ -514,7 +515,8 @@ def __getNestedValue(sNestedParam : str):
                     if errorType in str(error):
                         errorMsg = f"Could not resolve expression '{sNestedParam.replace('$$', '$')}'."
                 if errorMsg != '':
-                    errorMsg = errorMsg + f" Reason: {error}"
+                    errorMsg = errorMsg + f" Reason: {error}" if ' or slices' not in str(error) else \
+                                errorMsg + f" Reason: {str(error).replace(' or slices', '')}"
                 else:
                     errorMsg = f"The parameter '{sNestedParam.replace('$$', '$')}' is not available!"
                 raise Exception(errorMsg)
@@ -629,15 +631,7 @@ def __handleDotInNestedParam(sNestedParam : str) -> str:
                 rootVar = re.search(pattern, var[0], re.UNICODE)[0]
                 sRootVar = __handleDotInNestedParam(rootVar) if "." in rootVar else rootVar
                 sVar = var[0].replace(rootVar, sRootVar)
-            if re.search(r"\[\s*'[\s\-]*\d+\s*'\s*\]", sVar):
-                try:
-                    tmpValue = __getNestedValue(sVar)
-                except:
-                    errorMsg = f"{rootVar.replace('$$', '$')} expects integer as index. Got string instead in {sNestedParam}"
-                    self.__reset()
-                    raise Exception(errorMsg)
-            else:
-                tmpValue = __getNestedValue(sVar)
+            tmpValue = __getNestedValue(sVar)
             if bConvertToStr and (isinstance(tmpValue, list) or isinstance(tmpValue, dict)):
                 dataType = re.sub(r"^.+'([a-zA-Z]+)'.*$", "\\1", str(type(tmpValue)))
                 self.__reset()
diff --git a/JsonPreprocessor/JsonPreprocessor.pdf b/JsonPreprocessor/JsonPreprocessor.pdf
index b3718102..dedf3330 100644
Binary files a/JsonPreprocessor/JsonPreprocessor.pdf and b/JsonPreprocessor/JsonPreprocessor.pdf differ
diff --git a/packagedoc/additional_docs/The JSONP format.tex b/packagedoc/additional_docs/The JSONP format.tex
index c33f334b..c5f74fd9 100644
--- a/packagedoc/additional_docs/The JSONP format.tex	
+++ b/packagedoc/additional_docs/The JSONP format.tex	
@@ -603,7 +603,7 @@ \section{Overwrite parameters}\label{overwrite-parameters}
 
 \vspace{2ex}
 
-Using composite data types inside strings causes errors:
+Using composite data types inside strings is not supported:
 
 \begin{pythoncode}
 "newparam6" : "prefix_${listval}_suffix"
@@ -615,10 +615,18 @@ \section{Overwrite parameters}\label{overwrite-parameters}
 "newparam7" : "prefix_${dictval}_suffix"
 \end{pythoncode}
 
-\textbf{TODO:} \href{https://github.com/test-fullautomation/python-jsonpreprocessor/issues/249}{Parameter substitution needs to be limited}
+\vspace{2ex}
+
+Result for \pcode{"newparam6"}:
 
 \vspace{2ex}
 
+\begin{pythonlog}
+The substitution of parameter '${listval}' inside the string value 'prefix_${listval}_suffix' is not supported! Composite data types like lists and dictionaries cannot be substituted inside strings.
+\end{pythonlog}
+
+\newpage
+
 \textbf{Value of a single element of a parameter of nested data type}
 
 To access an element of a list and a key of a dictionary, we change the content of file \plog{componentB.2.jsonp} to:
@@ -998,7 +1006,7 @@ \section{Dynamic key names}
 \end{pythoncode}
 
 The value of \pcode{newparam1} is defined by an expression that is encapsulated in quotes and contains - beneath hard coded parts - a dollar operator expression
-that is the dynamic part.
+(that is the dynamic part).
 
 The same is also possible on the left hand side of the colon. In this case the name of a parameter is created dynamically.
 
@@ -1040,7 +1048,7 @@ \section{Dynamic key names}
 
 \vspace{2ex}
 
-This will not work:
+This will not work (because of a key with name \pcode{A_2} does not yet exist):
 
 \vspace{2ex}
 
@@ -1054,7 +1062,7 @@ \section{Dynamic key names}
 \textbf{Outcome:}
 
 \begin{pythonlog}
-<TODO: error message>
+A substitution in key names is not allowed! Please update the key name "${strval}_2"
 \end{pythonlog}