But you’ve shown us a UI entered rule, not a rule from a xxx.rules
file as used in 2018?
Right.
As described, this is a new rule i created, which calls the text-coded rule, as soon as movement is recognized by the presence sensor 
It’s a bit tricky, but the error was caused by changed import in version 3 in combination with OH not loading the import, when it is not restarted.
Args … the script seems to be not ok anymore (due to changed environment i guess?)
The script runs now, but it’s buggy.
[ERROR] [.internal.handler.ScriptActionHandler] - Script execution of rule with UID 'universaldimmer-1' failed: 'plusMillis' is not a member of 'java.time.ZonedDateTime'; line 69, column 27, length 22 in universaldimmer
The light is dimmed by one step (which is set as the 3rd parameter) and stops then. It’s not repeated until the set destination value (the 1st variable).
So to be precise: when i turn my light on by hand to 40% and start the script with as follows:
Dimmer,0,2000,10,Lampe_Helligkeit
The dimmer is set from 40% to 30%, then 30% to 38%, and again 38% to 30% and the script stops …
Also found a solution for this.
You need to change to lines to make it work nice and smooth 
now.plusMillis(mytime)
must be changed to
now.toInstant().plusMillis(mytime).atZone(now.zone)