first of all you want to get a notification every 5 seconds? if not change the interval in allestemplate to something like 15m or even higher.
Your imports should contain only the name of the template, the brackets [] are wrong.
Iam not sure if your assign works, because you do a assignt to the string true, it should look like
assign where host.enable_notification
Thats a short form for (bolean) variables or variables that are set with whatever they contain as long it is not false.
Regards,
Carsten
P.S.: please format your configuration posts in the future for better readability