Date Issue (Excel VBA)

I know Excel uses numbers for dates but the code below is not working...

    
    Dim erdate As String

valid = False
    Do Until valid = True
    erdate = Application.InputBox(prompt:="Enter E.R. Date", Title:="E.R. Date", Left:=300, Top:=250, Type:=2)
    If erdate <> Empty And erdate <> "False" Then
            valid = True
        End If
    Loop
    
'***** Begin ER date validation
'*      If ER Date is not between 07/01/08 & 11/30/10 then Exit Sub
'*
'*
    erdate = CDate(erdate)
    Select Case erdate
        Case 39630 To 40512
        Case Else
            MsgBox ("Please select Appropriate Analysis Spreadsheet for the Date of Service")
            Application.StatusBar = "Ready"
            Exit Sub
    End Select