That's not how PPLNS works, the window of shares that gets a reward is constantly changing and old shares that are outside of the window get discarded. If the effort for a found block is >100% , then shares outside of that 100% are discarded. So this is likely what happened with your shares.
Questions
Is it possible you stopped mining before a block was found and that by the time the block was found your shares were out of the window?
that could be. I let it run for several hours.Then I waited until a payout comes. I thought then everyone gets something from his shares
That's not how PPLNS works, the window of shares that gets a reward is constantly changing and old shares that are outside of the window get discarded. If the effort for a found block is >100% , then shares outside of that 100% are discarded. So this is likely what happened with your shares.
Shit. Ok thanks