Change WordPress user roles and capabilities › Forums › Bug Reports › Msg – Sorry, you are not allowed to access this page. › Reply To: Msg – Sorry, you are not allowed to access this page.
Try to deactivate URE plugin and activate it back. For some reason your administrator role did not receive URE’s superadmin permissions, like ‘ure_manage_options’, etc. URE tries to grant them to ‘administrator’ role on its activation.