Apparently I didn’t make myself very clear in my question …
I start all over again 
So, I try to write some code with a"Class". (Iused several times in “Processing P3”).
I took an example from Dan Shiffman (2D Ray Casting …).
When I run this code in the “Web editor”, it runs fine.
Now, when running “localy” by executing “P5.exe” from my HDD (see below)
Now I get an error … 
I hope this makes my problem more clear …
Roland