American Greetings Corp. The black SpongeBob was a goof in printing, the card company says. Wal-Mart offers refunds but won't stop sales. American Greetings Corp. calls it a regrettable printing error. Somehow, boxes of SpongeBob SquarePants Valentine's Day cards are popping up in local Wal-Mart stores -- but the popular cartoon character found inside isn't his traditional yellow color... AN UN-FUNNY VALENTINE: Greeting card picture evokes race stereotype |