The rendering was paused for most of Thursday and Friday as the Mapnik rendering database was being reloaded from the most recent planet dump. This happens ever month or two to ensure that everything gets refreshed. There are some features like the coastline which do not get updated by the normal minutely diffs.

The server may be busier than normal over the next 24 hours but it should render your changes soon.

Should be resolved now. See the comments on http://trac.openstreetmap.org/ticket/2129

The admin_level=4 boundary is starting to show up here:
http://www.openstreetmap.org/?lat=-6.0282&lon=35.2895&zoom=12&layers=B000FTFT