I can add and search in 2009 in Google Calendar. What error are you getting?

When using the "create event" or the "quick add" feature, it seems to work but then the event doesn't show in the calendar (as bold day when you scroll to the specific month), and when I search for a keyword of this event (e.g. "test2009") there will be an empty search result page... even though this result page to the right side claims that it found 1 event. When I create an event in say 2007 all works fine...

You can search up to 5881580.

Tangentially, I recetly passed 15,000 searches (since they started counting)