I imported customer data into Mappoint from excel and then created sales territories manually by selecting zip codes and adding them to a sales area.

I'm trying to modify the territories but when I open the map it no longer displays the zip codes. I tried zooming in and out, but it doesn't make a difference. If I switch geographies then the zip codes show up, but I lose all of the territories I had created previously.

Any suggestions as to what I am missing here?