http://assets.nagios.com/downloads/nagi ... vel.tar.gz
Check your PHP timezone settings, it sounds like it could either be related to DST or the UTC offset is off by an hour. The following wiki shows where to set your PHP timezone settings.I suspect ours was started by altering the timezone to the correct city we are located in. Scouring around some other nagios forums it looks like maybe the SQL backend might have issues with certain timezones but that is just a stab in the dark. The timezone was updated and then not long after we updated to 2009R1.4B and this is when the Event Data Stale errors appeared. We are located Brisbane, Australia GMT +10 but no daylight savings. The Event data always says it is out 1hr and about 40 secs and daylight savings time is +1 hr so figured might be related to that.
http://support.nagios.com/wiki/index.ph ... e.22_Error