It can not be automatically accept the meeting notification

It has formed a VBA would get an error in 
the "Outlook2010".

I am a beginner.
"Run-time error '91': 
Object variable or With block variable not set."
An error in the mark of the place.

What I have tried:

<pre lang="VB.NET">Public Sub DisplaySubjectByRule(ByRef objItem As MeetingItem)
Dim myNameSpace As Outlook.NameSpace 
Dim myFolder As Outlook.Folder 
Dim myMtgReq As Outlook.MeetingItem 
Dim myAppt As Outlook.AppointmentItem 
Dim myMtg As Outlook.MeetingItem
　Set myNameSpace = Application.GetNamespace(&quot;MAPI&quot;) 
　 Set myFolder = myNameSpace.GetDefaultFolder(olFolderInbox) 
　 Set myMtgReq = myFolder.Items.Find(&quot;[MessageClass] = &#39;IPM.Schedule.Meeting.Request&#39;&quot;) 
Set myMtgReq2 = myFolder.Items.Find(&quot;[MessageClass] = &#39;IPM.Schedule.Meeting.Canceled&#39;&quot;)
If TypeName(myMtgReq) &lt;&gt; &quot;Nothing&quot; Then 
　Set myAppt = myMtgReq.GetAssociatedAppointment(True) 
　 Set myMtg = myAppt.Respond(olResponseAccepted, True) 
　myMtg.Send  'Error!
ElseIf TypeName(myMtgReq2) = &quot;Nothing&quot; Then 
　Set myAppt = myMtgReq2.GetAssociatedAppointment(False) 
　 Set myMtg = myAppt.Respond(olResponseAccepted, False) 
　myMtg.Send  'Error!
myMtg.Delete 
End If 
End Sub</pre>