Why so many stale shares?
I tried all the pools and I always got around 10-15% refused shares using Java Miner.
Are you experiencing the same thing?
What is your Avg Submit RTT? (Find this information while mining.)
Nonces: Attempted: 6 Rejected: 0 Eff: 100.00% Avg Hash/nonce: 2867 Avg Submit RTT: 964ms