Can't set initial value

I’m trying to set the initial value of a DateTime Item (named Opening1), but I’m failing, WHY???

I have this in a rule:

logInfo("OpeningTimes", "Opening1 = {}", Opening1)
Opening1.postUpdate(now)

and I’m getting this:

12:08:56.755 [INFO ] [.smarthome.model.script.OpeningTimes] - Opening1 = Opening1 (Type=DateTimeItem, State=NULL, Label=null, Category=null)
12:08:56.771 [ERROR] [ntime.internal.engine.ExecuteRuleJob] - Error during the execution of rule Call Lambda: An error occured during the script execution: Could not invoke method: org.eclipse.smarthome.model.script.actions.BusEvent.postUpdate(org.eclipse.smarthome.core.items.Item,org.eclipse.smarthome.core.types.State) on instance: null

Why is the instance null, that should be the Item Opening1, which is logged in the line above???

Perhaps it is the ‘now’ that is null - where do you define that?

The now? I don’t think so, I’m using it already in other spots to get the actual time without any declaration.

Stupid .Me, it was the “now”, but in another way. The “.toString” made it work.
Sometimes I think I’m blind!