Im ot sure buy maybe  MPH stratum difficulty is set too high. When I connect with a cpu miner the pool difficulty sets it at 5 and it takes so long to get a share that MPH shows my cpu miner is offline until it finds a share and then drops off again until I find the next share. When I connect to f2pool stratum difficulty is set to to .499 and i get multiple shares immediately. I also tried to set difficulty in the bat file but it seems to have no effect. I have emailed MPH but no response yet.