We've had a few seldom crashes overnight, and I apologize for that. Reading through the main PPCoin thread, it seems that ppcoind has a memory leak that causes it to crash. This is in conjunction  with what I found - pushpool and mmcFE are always still running whenever a crash happens, but ppcoind is mysteriously killed. I am setting up a cron job to automatically restart ppcoind every few hours. Thanks everyone for your patience