Zugferd: fix

Interfaces/ZUGFeRDInterface/FileGroups.vb

@@ -3,7 +3,7 @@ Imports System.Text.RegularExpressions
 Imports DigitalData.Modules.Logging
 
 Public Class FileGroups
-    Private _logger As Logger
+    Private ReadOnly _logger As Logger
 
     Public Sub New(LogConfig As LogConfig)
         _logger = LogConfig.GetLogger()
@@ -25,7 +25,7 @@ Public Class FileGroups
             Dim oMessageId = GetMessageIdFromFileName(oFile.Name)
 
             If oMessageId Is Nothing Then
-                _logger.Warn("File {0} did not have the required filename-format!", oMessageId)
+                _logger.Warn("File {0} did not have the required filename-format!", oFile.Name)
                 Continue For
             End If