Zugriffsverletzung bei Adresse 0043815C in Modul 'xxx.exe'. Lesen von Adresse

[Moien]

Hallo Zusammen,

Ich habe ein Delphi-Programm und versuche, über mein Programm Variablen auf den OPC UA-Server zu schreiben. Ich erhalte den folgenden Fehler:
"TOPCClient.WriteItem - Exception: Zugriffsverletzung bei Adresse 0043815C in Modul 'xxx.exe'. Lesen von Adresse 00000000".

Ich habe einen Teil meines Codes hier kopiert, in dem der Fehler auftritt.

Delphi-Quellcode:

// -----------------------------------------------------------------------------
// WriteItem - Write OPCUA Item
// -----------------------------------------------------------------------------
function TOPCClient.WriteItem(Name: String; ItemValue: Variant): Boolean;
Var
  I : Integer;
  ItemFound : Boolean;
  label
  GoToWriteToOPCServer;
begin
  ItemFound := False;
  Result    := FALSE;
  try
    for I := 0 to Length(OPCServerItemArray)-1 do begin
      if (AnsiMatchStr(Name, OPCServerItemArray[I].ItemName)) then begin
        ItemFound :=  True;
        WriteToOPCServerArray[WriteIndex].ItemName := Name;
        WriteToOPCServerArray[WriteIndex].Value := ItemValue;
        WriteToOPCServerArray[WriteIndex].Source := OPCServerItemArray[I].Source;
        WriteIndex := WriteIndex+1;
        Result := True;
        GoTo GoToWriteToOPCServer;
      end;
    end;

    if not(ItemFound) then  begin
      Meldung(0,'TOPCClient.WriteItem: ' + Name + ' (is not found)');
    end;
    GoToWriteToOPCServer:
    if (WriteIndex = NoVarToWrite)then begin
      WriteMultipleIdx := WriteIndex;
      WriteIndex:= 0;
      WriteMultipleItems;
    end else if (WriteIndex > NoVarToWrite) then begin
      Meldung(0,'TOPCClient.WriteItem - Exception: The write array is too long!'+ 'WriteIndex = '+ IntToStr(WriteIndex));
    end;

  except
    on E: Exception do begin
      Meldung(0,'TOPCClient.WriteItem - Exception: ' + E.Message + '  info: ' + Name + '  WriteIndex: ' + IntToStr(WriteIndex) + ' I = ' + IntToStr(I));
    end;
  end;
end;

// -----------------------------------------------------------------------------
// WriteMultipleItem - Write OPCUA Item
// -----------------------------------------------------------------------------

Procedure TOPCClient.WriteMultipleItems;
Var
  I : Integer;
  Results : OleVariant;
  ExpandedText : WideString;
begin
  SetLength(WriteValueArguments,WriteMultipleIdx);
  try
    if (connected) then begin
      for I := 0 to WriteMultipleIdx-1 do begin
        WriteValueArguments[I] := CoUAWriteValueArguments.Create;
        WriteValueArguments[I].EndpointDescriptor.UrlString := Url_String;
        ExpandedText := 'nsu='+ nsu + ';s=' + S0 + '.' + WriteToOPCServerArray[I].Source + '.' + WriteToOPCServerArray[I].ItemName;
        WriteValueArguments[I].NodeDescriptor.NodeId.ExpandedText := ExpandedText;
        WriteValueArguments[I].Value := WriteToOPCServerArray[I].Value;
      end;

      WriteArguments := VarArrayCreate([0, WriteMultipleIdx-1], varVariant);
      for I := 0 to WriteMultipleIdx-1 do begin
        WriteArguments[I] := WriteValueArguments[I];
      end;

      TVarData(Results).VType := varArray or varVariant;
      TVarData(Results).VArray := PVarArray(OPCUAClientMultiWrite.WriteMultipleValues(
      PSafeArray(TVarData(WriteArguments).VArray)));
    end else begin
      Meldung(0,'TOPCClient.WriteAllItems: not connected to the OPC UA Server');
    end;
  except
    on E: Exception do begin
      Meldung(0,'TOPCClient.WriteMultipleItems - Exception: ' + E.Message);
    end;
  end;
end;

Ich würde mich über Ihre Unterstützung freuen.

LG
Moien