StaxRip 2.1.4.4 empty source filter file type error

TargetInvocationException (2.1.4.4)

Exception has been thrown by the target of an invocation.

System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.InvalidOperationException: Failed to compare two elements in the array. ---> System.NullReferenceException: Object reference not set to an instance of an object.
   at StaxRip.StringPair.CompareTo(StringPair other) in D:\Projekte\VB\staxrip\General\General.vb:line 810
   at System.Collections.Generic.GenericArraySortHelper`1.InsertionSort(T[] keys, Int32 lo, Int32 hi)
   at System.Collections.Generic.GenericArraySortHelper`1.IntrospectiveSort(T[] keys, Int32 left, Int32 length)
   at System.Collections.Generic.GenericArraySortHelper`1.Sort(T[] keys, Int32 index, Int32 length, IComparer`1 comparer)
   --- End of inner exception stack trace ---
   at System.Collections.Generic.GenericArraySortHelper`1.Sort(T[] keys, Int32 index, Int32 length, IComparer`1 comparer)
   at System.Array.Sort[T](T[] array, Int32 index, Int32 length, IComparer`1 comparer)
   at System.Collections.Generic.List`1.Sort(Int32 index, Int32 count, IComparer`1 comparer)
   at StaxRip.MainForm.ShowSettingsDialog() in D:\Projekte\VB\staxrip\Forms\MainForm.vb:line 3544
   --- End of inner exception stack trace ---
   at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor)
   at System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj, Object[] parameters, Object[] arguments)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at System.Reflection.MethodBase.Invoke(Object obj, Object[] parameters)
   at StaxRip.CommandManager.Process(Command command, List`1 params) in D:\Projekte\VB\staxrip\General\General.vb:line 1096