I have to admit that i have a lot of rejected shares too, around 8%, and i don't know how but my miner said that stratum lost 3032 shares because of lost connection and "Pool - 0" something like that, after, he was waiting work from the pool, i can't remember exactly :s (edit: note that my connection was up with no packet loss or other)
After, i switched to dime.ext-pool with under 1% of rejected shares, i mean that maybe there is a little problem on your side @lulupon ?
I will give another try on your pool soon I promise