And the winner is....KAIBACH !!!!   :-)

I set Vista to globally use the period separator and that fixed it.

Ok, it's more a workaround than a fix, because as a German I'd rather prefer my sytem to adhere to german spelling.
But at least that should give SM enough info to permanently fix it.

Funny thing is, I still reverted back to SR-1 as with SR2.1 rendering was noticeable slower !
Firefly lost 2 seconds on a "Nude figure with hair" and half a minute on a "Figure with a few scene props".

(Timed with the "render Firefly" script)

Again, thanks to Kaibach for steering me into the right direction.