I have a m3 lite microsd with 256 mb sandisk card. I just bought this set about 2 weeks ago. Recently, I've been getting some save errors saying "Auto backup file not found" when I start up the m3 after shutting it down. Sometimes, it doesn't even put up a save screen and goes straight to the m3 menu right after I play a game. It's been working fine for 2 weeks until all of a sudden this started happening. What is wrong?