RaceOnRCWCleanup was detected

The application was written in VS 2008 and was working on my win xp desktop and when update to win 7 64 bit the err. occured Attemp to read or write the protected memory

The app has now been updated to VS 2012 and still the err. persists

on debuging following err. is occurring in following code An attempt has been made to free an RCW that is in use

Code:

---

        Dim closeapp As Boolean = False

        Do While closeapp = False
            If OpenWindow = NewWindow.SelUser Then
                OpenWindow = NewWindow.MainMenu
                SetUser()
            ElseIf OpenWindow = NewWindow.MainMenu Then
                OpenWindow = NewWindow.End
                MainMenu.ShowDialog()
                MainMenu.Dispose()
            Else : closeapp = True
            End If
        Loop

---

The err. occurs when i try to load the form which contains CrystalReportViewer

Please Help