Solved - Problem with rule - error: the name 'Undefined' cannot be resolved to an item or type -- wifi detection

having issue using a rule in OH2. With OH1 all works fine. i am using the rule from https://github.com/openhab/openhab/wiki/Samples-Tricks#check-presence-by-detecting-wifi-phonestablets
and having now the following error:

2016-10-23 12:05:00.271 [ERROR] [ntime.internal.engine.ExecuteRuleJob] - Error during the execution of rule Periodically check presence: An error occured during the script execution: The name ‘Undefined’ cannot be resolved to an item or type.

Any hints are appreciated. thanks in advanced.

my fault…

RTFM – Migration from OH 1.x to OH 2 Tutorial