[logback-user] timstmp

How do I convert the timestmp stored in MySQL DB. In the database it looks: 1221685679781 but when I convert this with PHP and print it, I get: 06/09/2030 : 16:28:37:000000 What's seems to be a problem? Where the 2030 year comes from? Any Ideas how to convert this properly? Thanks Gregg.