After 9 hours of runtime p2pool shows:
Pool: 693MH/s in 41521 shares Recent: 10.93% >75MH/s Shares: 645 (112 stale)
So 112 of 645 shares are stale shares this is a 17,4% stale rate.
Something is still wrong and i don't know the root cause.
While this is a bit high, some amount of stales will always be normal since work is invalidated within an average of 5 seconds. However, 'p2pool shares' are not exactly the same as normal shares: While you don't get credit for them, they can still cause the pool to solve a block. Because of this, as long as everyone using p2pool has approximately the same amount of stales, nobody is losing anything because of them.
I'm working on more techniques in p2pool and the miners to reduce the amount of stales. The lowest I've gotten it is about 8%.
Has p2pool found any block yet?
No. :/ With the current pool power, there was only about a 10% chance of this happening before now.