https://en.bitcoin.it/wiki/P2Pool#StalesCould anybody be so kind to explain in more details, what does this mean?
On P2Pool stales refer to shares which can't make it into the sharechain. Because the sharechain is 20 times faster than the Bitcoin chain many stales are common and expected. However, because the payout is PPLNS only your stale rate relative to other nodes is relevant; the absolute rate is not.
What's PPLNS got to do with it?