Getting checks working right

I am new to Nagios, and am trying to get a disk space check working. I had a problem, searched, think I found an answer… but I don’t know how to confirm. I scheduled a test for 1 minute in the future, but does lack of an email mean the test passed (even though I expected it to fail), or that the test just didn’t happen, or because something else went wrong?

The details for the host don’t help a whole lot…

Host Status:
UP
Status Information:
Performance Data:
Current Attempt: 1/10
State Type: HARD
Last Check Type: ACTIVE
Last Check Time: 12-31-1969 16:00:00
Status Data Age: N/A
Next Scheduled Active Check: N/A
Latency: 0.000 seconds
Check Duration: 0.000 seconds
Last State Change: 03-26-2007 14:05:17
Current State Duration: 484d 20h 6m 35s
Last Host Notification: N/A
Current Notification Number: 0
Is This Host Flapping? N/A
Percent State Change: N/A
In Scheduled Downtime?
NO
Last Update: 07-23-2008 10:11:41

Last check was in 1969? I don’t think so. Host has been up for 92 days, not 484

How do I clear out this bad info and ensure that checks are happening correctly?