Egg received Day-Care Couple
Date Jan 31, 2012
Hatched/Met PokéTransfer
Date Jan 21, 2012
hatched date before egg received is why it's a warning.
it's not red so it's not illegal, it's just a mistake hackers would sometimes make. (date)changing DSes is the cause in your case, so don't worry about it. If you really care about having it all green, just download the pkm, change it so both dates match, and then reupload the pkm.