2. The network hashrate is 350 MHash/sec, after only 3 days.
huh so p2pool have 10% of network

keep going to mine in p2pool!
I have many payouts from
http://pool.hostv.pl:9555/BTW: p2pool give transaction fee to all miners wow!
BTW2: remeber one thing... p2pool give payouts from shares in last few block... so you must mine about one hour to have full payout.
You said your server was in France, I'm from France and I can say your implementation is crappy. Sorry but I get 50% of rejects shares. When I mine on my own LTC pool (hosted on OVH too, at Roubaix, France) I get less than 1.5% rejects. Just sayin', I got 36ms of ping to your server.