Protected Pivot Table Error on Open

I have a workbook with the following macros:

The First macro password protects every sheet when the workbook is closed.

Const pw = "dashboard"
Sub Auto_Close()
    Dim Wsht As Worksheet
    For Each Wsht In Worksheets
        Wsht.Protect Password:=pw
    Next Wsht
End Sub

The second macro allows a user to unprotect all sheets at once.

Sub UnprotectAll()
    ans = LCase(Application.InputBox("Enter password to continue"))
    If ans <> LCase(pw) Then
        MsgBox "Incorrect Password", vbExclamation, "Warning"
        Exit Sub
    End If
    Dim Wsht As Worksheet
    For Each Wsht In Worksheets
        Wsht.Unprotect Password:=pw
    Next Wsht
End Sub

I'm in Excel 2007. For every worksheet that has a pivot table, I receive a messagebox that says "Cannot edit PivotTable on protected sheet." when I open the workbook.

What's the best way to deal with this error?