trigger is unknown?

[radamand]

Can someone explain to me why the trigger below is not "True"??
Its a simple zabbix agent ping, as you can see, the trigger is set such that "last(0)}#1", I killed the agent on the monitored server and the status of the trigger changes to "unknown", shouldn't it be "True" since "unknown" does NOT equal "1"??

http://i522.photobucket.com/albums/w341/radamand/unknown.png

[radamand]

After trying many different things to fix this I found one way that almost works.
changing the trigger to
{ripper15:agent.ping.nodata(300)}=1

allows the trigger to turn to "True", however for some reason the Action that I have specified never executes.....