Ok, is see now, any new fixture i put in is not responding !
so no problem with the specific Led spere or Octostrip !
I have to say, that I have this problem, after importing multiple Google sketchup models. (my file is now + 40 MB)
It was something very stupid.
I had created a new layer and the "simulation" option (in layers tab) was not checked.
then the new imported fixtures are visible but will not respond.
so, solved.