Ok, now this works.
Now I have another problem: I can't read out the frame in the scripted box.
if i do so, an error message appears.
When I write something like
Math.sin(frame/100.00)
in the controller of a servo, it works, but if I write
setVar("a",frame/100.00)
and into the controller
getVar("a")
the error message occurs.
That's really odd...
edit: It seems, that my old SP models work well, but if I copy the code into a new Scripted-box ob an object, it doesn't work anymore. Maybe I should get an older Version of SP?